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UNITED STATES DEPARTMENT OF COMMERCE

Maurice H. Stans, Secretary

U> S NATIONAL BUREAU OF STANDARDS • A. V. Astin, Director

* * e

Molten Salts: Volume 2

Section 1. Electrochemistry of Molten Salts: Gibbs Free Energies

and Excess Free Energies From Equilibrium-Type Cells

G. J. Janz* and Chr. G. M. Dijkhuis*

Section 2. Surface Tension Data

G. J. Janz,* G. R. Lakshminarayanan,*

R. P. T. Tomkins,* and J. Wong*

*This report was prepared under contract at the Molten Salts Data Center,

Rensselaer Polytechnic Institute, Troy, N.Y. 12180

NSRDS-NBS 28

Nat. Stand. Ref. Data Ser., Nat. Bur. Stand. (U.S.), 28, 116 pages (August 1969)

CODEN: NSRDA

Issued August 1969

For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 — Price $2.75
JAN 1 2 1970

146208

i&C too

.USIS

‘Co.i??, I'

ftj 47

/ Library of Congress Catalog Number: 68—60051
Foreword

The National Standard Reference Data System is a Government-wide effort to provide for the

technical community of the United States effective access to the quantitative data of physical

science, critically evaluated and compiled for convenience, and readily accessible through a

variety of distribution channels. The System was established in 1963 by action of the President’s

Office of Science and Technology and the Federal Council for Science and Technology.

The responsibility to administer the System was assigned to the National Bureau of Standards and an Office of Standard Reference Data was set up at the Bureau for this purpose. Since

1963, this Office has developed systematic plans for meeting high-priority needs for reliable ref- erence data. It has undertaken to coordinate and integrate existing data evaluation and compilation

activities (primarily those under sponsorship of Federal agencies) into a comprehensive program,

supplementing and expanding technical coverage when necessary, establishing and maintaining

standards for the output of the participating groups, and providing mechanisms for the dissemination of the output as required.

The System now comprises a complex of data centers and other activities, carried on in

Government agencies, academic institutions, and nongovernmental laboratories. The independent

operational status of existing critical data projects is maintained and encouraged. Data centers

that are components of the NSRDS produce compilations of critically evaluated data, critical

reviews of the state of quantitative knowledge in specialized areas, and computations of useful

functions derived from standard reference data. In addition, the centers and projects establish

criteria for evaluation and compilation of data and make recommendations on needed modifications

or extensions of experimental techniques.

Data publications of the NSRDS take a variety of physical forms, including books, pamphlets,

loose-leaf sheets and computer tapes. While most of the compilations have been issued by the

Government Printing Office, several have appeared in scientific journals. Under some circumstances, private publishing houses are regarded as appropriate primary dissemination mechanisms.

The technical scope of the NSRDS is indicated by the principal categories of data compilation projects now active or being planned: nuclear properties, atomic and molecular properties,

solid state properties, thermodynamic and transport properties, chemical kimetics, colloid and

surface properties, and mechanical properties.

An important aspect of the NSRDS is the advice and planning assistance which the National

Research Council of the National Academy of Sciences-National Academy of Engineering provides. These services are organized under an overall Review Committee which considers the

program as a whole and makes recommendations on policy, long-term planning, and international

collaboration. Advisory Panels, each concerned with a single technical area, meet regularly to examine major portions of the program, assign relative priorities, and identify specific key problems in need of further attention. For selected specific topics, the Advisory Panels sponsor subpanels which make detailed studies of users’ needs, the present state of knowledge, and existing

data resources as a basis for recommending one or more data compilation activities. This assembly

of advisory services contributes greatly to the guidance of NSRDS activities.

The NSRDS—NBS series of publications is intended primarily to include evaluated reference

data and critical reviews of long-term interest to the scientific and technical community.

A. V. Astin, Director.

Ill
Abstract

This book consists of two sections as follows:

Section 1

The critical evaluation of excess free energies of binary molten salt mixtures

with a common ion from equilibrium-type electrochemical cells is described in

this report. For this purpose calculations using the original emf data were sys- tematically undertaken to establish comparisons of free energy values of various

workers that would be significant. The reversibility of electrodes is investigated

by comparing the electromotive force of cells with a single molten salt as liquid

electrolyte with thermochemical data.

Section 2

Data on the surface tensions of single salt melts have been systematically

collected and evaluated. Results are given for 106 inorganic compounds over a range of temperatures where available.

Key words: Critically evaluated data; equilibrium electrochemical cells; excess entropies; excess Gibbs free energies; Gibbs free energies; molten salt mixtures; molten salts; surface tension;

thermodynamics of molten salts. Acknowledgments

The participation of T. G. Coker, F. W. Dampier, P. K. Lorenz, H. Siegenthaler,

and A. Timidei in various stages of this work at Rensselaer is acknowledged with

pleasure.

IV
Contents

Page Section 1. Electrochemistry of molten salts: Gibbs free energies and excess

free energies from equilibrium-type cells 1 G. J. Janz and Chr. G. M. Dijkhuis.

Section 2. Surface tension data 49

G. J. Janz, G. R. Lakshminarayanan, R. P. T. Tomkins, and J. Wong.

V

Molten Salts: Volume 2

Section 1. Electrochemistry of Molten Salts: Gibbs Free Energies and

Excess Free Energies from Equilibrium-Type Cells

G. J. Janz* and Chr. G. M. Dijkhuis*

The critical evaluation of excess free energies of binary molten salt mixtures with a common ion from equilibrium-type electrochemical cells is described in this report. For this purpose calculations using the original emf data were systematically undertaken to establish comparisons of free energy

values of various workers that would be significant. The reversibility of electrodes is investigated

by comparing the electromotive force of cells with a single molten salt as liquid electrolyte with thermochemical data.

Key words: Critically evaluated data; equilibrium electrochemical cells; excess entropies; excess Gibbs free energies; Gibbs free energies; molten salt mixtures; molten

salts; thermodynamics of molten salts.

Contents

Page

1. Introduction 1 2. Units, fundamental constants, and symbols 1 3. Theoretical principles and method of calculation 2

3.1. Statistical Analysis of Data 3

4. Uncertainties 3

5. Discussion 3

5.1. Cells 3

5.2. Individual mixtures 6

6. Cumulative table of excess free energies 27

7. Tables of E° values and excess properties for individual mixtures 28

8. References 47

9. Compound index 48

1. Introduction

Thermodynamic data of molten salts can be

gained by various experimental techniques, e.g., heats of mixing calorimetry [1], vapor pressure

measurements [2], cryometry [3], and electrochemical cells [4].

1 Next to high temperature heats of

mixing calorimetry, the measurement of the electromotive force of electrochemical cells is possibly

the method capable of greatest precision and accuracy, providing due attention is directed to certain

features of the experimental work [5J. The calculation of excess free energies of molten salt mixtures

from concentration cell data is well understood

[3, 4, 5, 6], and while a considerable amount of

literature in this area exists [5, 6J. it is difficult to obtain meaningful results since the liquid junction

potential is generally unknown; this makes the

derived thermodynamic results uncertain. This

uncertainty does not arise in the calculation of free

energies and excess free energies from emf data of

*Molten Salts Data Center, Rensselaer Polytechnic Institute, Troy, N.Y. 12180.

1 Figures in brackets indicate the literature references on page 47.

equilibrium-type cells, i.e. cells with two different

electrodes. The critical evaluation of excess free

energies of binary molten salt mixtures with a common ion from equilibrium-type cells is described in this report. The following aspects are considered: units, fundamental constants and symbols; theoretical principles and method of calculation; uncertainties and discussion of some cells; and the guide-lines for the critical evaluation of each

contribution.

2. Units,* Fundamental Constants,

and Symbols

The fundamental constants are those adopted by

the National Bureau of Standards (NBS Technical

News Bulletin, October 1963). All energy values

are expressed in terms of the thermochemical

calorie or in terms of the millivolt.

*The NBS Office of Standard Reference Data, as administrator of the National Standard Reference Data System, has officially adopted the use of SI units for all NSRDS publications, in accordance with NBS practice. This publication does not use SI units because contractual commitments with the author predate establishment

of a firm policy on their use by NBS. Appropriate conversion factors are found above. The NBS urges that specialists and other users of data in this field accustom themselves

to SI units as rapidly as possible.

1
Fundamental Constants

Symbol Name

N Avogadro Constant F Faraday Constant T Temperature in °K

t Temperature in °C

e Electronic Charge

R Gas Constant

cal Thermochemical

calorie

Value

6.02252 X 1023 ± 0.00028 X 10 23 /mol

96.487.0 ±1.6 C/mol

(23.060.9 ± 0.4 cal/V equiv)

0 °C= 273.15 °K

1.60210 x 10- 19 C

8.3143 ±0.0012 J/K mol

1.98716 ±0.00029 cal/deg mol

4.1840

J

By expressing the excess entropy ( S

E

) according

to the equation:

S

E = x(\— x) {a' + b'x + c'

2

) (4)

it follows similarly that:

s%xlx2 = a

' ~b' + 2(6' — c')x-\- 3c'x 2 (5a)

and

s%xl(l—x) 2 = a' + 2b'x + 3c'x 2 (5b)

Symbols and Terminology

G = Molar Gibbs free energy

GE = Excess molar Gibbs free energy

HE = Molar heat of mixing

S

E = Excess molar entropy of mixing

fx Ex = Excess chemical potential of component AX;

Partial excess molar Gibbs free energy of

mixing of component AX

h

E

AX — Partial excess heat of mixing of component AX

sf¥ = Partial excess molar entropy of mixing of

component AX

xax — Mole fraction of component AX. In a binary

mixture AX(x) , BX{ 1 — x) the mole fraction

of AX is NaxI (NAx + NBx)

E = Cell emf

z — Number of equivalents

3. Theoretical Principles and Method

of Calculation

The parameters a', 6', and c in eq 5 may be determined from an analysis of sEx/x2 or SgXl (l —x) 2 as a function of x. The excess chemical potentials (eq 3a and eq 3b)

and the excess entropies (eq 5a and eq 5b) can be

determined from experimental emf data. Consider

the cell: PbIPbChll — x), NaCl(jt)| Chi C (6)

The cell reaction is: Pb+ CI2 — PbCl2 (2 electron transfer) (7)

from which it follows: — 2EF — /Xpbcu — P-Pb

- f^ch (8)

If one now defines ideal solution behaviour by means

of the Temkin relation [8]

6+bCl2 P-pbCb ^ X AGbCU (^)

The following are the basic principles and

concepts used for the evaluation of excess free

energies and excess entropies from emf values of

equilibrium-type cells [7]. The excess molar Gibbs

free energy of mixing ( GE

) of a molten binary

mixture AX( 1—x), BX(x) may be expressed by

the equation:

G

E — x(l— x) {a + bx + cx2

) (1)

The expressions for the excess chemical potentials

of the components AX and BX {fx

%

x and /x%x ) follow

readily from eq 1 and the Gibbs-Duhem relation, i.e.

I1ax = [a — 6 + 2(6 — c)* + 3c*2 ]*2 (2a)

and

^hx — (a + 2bx + 3cx2

) (1 — x) 2 (2b)

The values of the constants a, 6, and c may be

obtained from a graphical analysis of ix Exlx 2 or

fx§xl ~ x)

2 as a function of the mole fraction, i.e.:

/XAx/x2 = a — 6 + 2(6 — c)* + 3cx2 (3a)

and

fXgXl(l — x) 2 = a + 2bx + 3cx2 (3b)

it can be shown from eqs 8 and 9 that

-2EF=fx°bCh + RT ln(l-^) +/AfbCl2 -/Xpb -Mci2

( 10)

For the case where the electrolyte is pure PbCk

(i.e. x— 0), the emf of this cell is given by:

2E°F = /Apbci2 — A4>b Mci2 (11)

Combining eqs 10 and 11 gives:

-2(E-E°)F = RTln(l-x) + ii$bCh (12)

When E and /jl are expressed in mV, the result is: — Prbch = 2 (E — E°)F A- 0. 19845

1 log(l-x) (13)

Thus it follows that from a knowledge of E, E° , and

x , a measure of the excess free energies can be

gained by this method.

The partial excess entropy can be gained from

the temperature dependence of the E values, i.e.

s Pbci2 — — (bixE

bCX2 /8t)x = 2(8£78f)*-2(S£/80x-0.19845 log(l-x) (14)

2
Thus 5pbCl2 may be gained from the temperature

dependence of E° and E or from the temperature

dependence of /u

1fbC , 2 (eq 13), whereas the parameters b' , and c in eq 4 may be obtained from an

analysis of sfibClJx2 as a function of x (eq 5). Thermodynamic properties of molten salts have

also been determined from cells in which glass

functions as a cation selective membrane. Consider

the cell

C|Cl2 |NaCl|glass|NaCl(l — *) , MgCl2 (:t) | CI2 1 C [9] ^ v

' ' ' I II (15)

The cell reaction was found to be [9, 10]

(NaCl), —* (NaCl)„ (16)

from which it follows that ~ EF = ( fXNaC\) u — (^NaCl)l (17)

Again defining ideal mixing behaviour by means of

the Temkin relation [8] and expressing E and /jl in

mV it follows that

A

tNaci = ^' + 0.19845 T log (1 —x) (18)

Excess free energies and excess entropies can now

be calculated from the experimental emf of cell( 15)

analogous to the procedure for cell (6). The values of E and E° (eq 13) are generally large

when compared to the difference quantity (E~E°),

so that the excess free energy by this method rests heavily on the determination of relatively small

values from the difference of two relatively much

larger numbers. The calculation of the (E — E°)

values has generally been by a graphical method.

While the graphical analysis provides a ready

assessment of the data, inspection showed that the

difference quantity (E — E°) should be evaluated by

a linear and a quadratic least squares analysis if reliable precisions are to be gained. The latter procedure was adopted in the present work. It was also

found that it was worthwhile to recalculate the free

energies and the excess free energies from the

literature emf data. These recalculations were

undertaken by following the guidelines and principles discussed in this section to establish a self- consistent set of results, with reliable precision

estimates, as required for meaningful intercomparison.

3.1.

Statistical Analysis of Data

Linear and quadratic equations of emf-temperature relationship were fitted to available sets of

experimental data by the method of least squares.

All calculations were with the digital computer

facilities at Rensselaer Polytechnic Institute and

double precision Fortran IV programs. The criterion

for choosing a linear or quadratic equation of best

fit for a set of emf-temperature data is the standard

deviation computed from the residuals and is defined by:

where Ae =the experimental emf value at each

temperature, Ac = the value calculated from the

least squares equation at the same temperature as Xe , n= number of experimental data points, and

q — number of coefficients in the least squares equation (2 for linear and 3 for quadratic). The standard

deviation 5 is used as the precision estimate.

4. Uncertainties

The cell emfs and the (E —E°) values (eq 12)

have been recalculated at various temperatures

by means of a linear and a quadratic least-squares

analysis of the literature data. The standard deviation in the temperature dependence of the emf

data was also calculated. Excess entropies have

been derived from “best fit” linear or quadratic

equations.

Experimental considerations and standard deviation in the temperature dependence of emfs were

taken into account for the evaluation of the parameters in the equation for the excess free energy

(eq 1) and in the equation for the excess entropy

(eq 4). An exact mathematical analysis was considered; however, it was found that the statistical

treatment was unsatisfactory since it was difficult to give sufficient weight to factors arising in experimental procedures. The problem of systematic

errors in various investigations is considered in

section 5.1. The intercomparison of various emf

studies with the same salt as the liquid electrolyte,

and the comparison of these values with thermochemical data [11,12,13] are used for this purpose.

Such comparisons establish the guide-lines for the

discussions in section 5.2 of the individual mixtures.

5. Discussion

5.1.

Cells

5.1.1.

Ag| AgCl|Cl2 |C.

[11, 16, 19, 20, 21, 22, 23, 24, 25, 26. 27]

The reported E° values of this cell are compared in table 1. Mixed potentials at the Ag electrode have

been reported and discussed [14, 15]. Although

Senderoff and Brenner [15] do not give a thermodynamically sound argument for the absence of

mixed potentials at the Ag electrode, it seems most

likely that differences in E° values between various

authors are mostly due to a nonequilibrium behaviour of the CI2 1 C electrode [16, 17, 18]. Small

differences might also be due to different corrections for the thermal emf of the Ag|C couple.

3
The investigation of Senderoff and Mellors [16J

appears to be the most thorough. The C electrode was pretreated in a Cl2 atmosphere for two hours

at 2300 °C. During the studies, the Cl2 pressure was controlled and electrolysis was used to attain

equilibrium rapidly. The Ag electrode was protected from chlorine gas by a quartz tube envelope

having a porous quartz disk at the bottom.

Table 1 shows that the E° values of Panish,

Newton, Grimes, and Blankenship [19, 20J are in

perfect agreement with the E° data of Senderoff

and Mellors [16J up to 900 & C; the values of Leonardi

and Brenet [2 1 J , Murgulescu and Sternberg [22]

and Salstrom [23] show a maximum departure of

10 mV at 900 °C. The Stern [24, 25] values differ

from Senderoff and Mellors [16] by 23 mV at 900 °C.

Panish, Newton, Grimes, and Blankenship [19, 20] use an experimental procedure similar to that of

Senderoff and Mellors.

Stern [24, 25 1 did not apply a correction for the

thermoelectric effect. Other factors, such as imperfect pretreatment of the Cl2 1 C electrode may

also contribute in part to the difference of 23 mV.

The unstable potentials in the dilute AgCl mixtures

could be due to oxide impurities and dissolved

oxygen in the Ag wire. This would also explain in

part the difference in ( 8E°I8T ) between Stern

[24, 25J and Senderoff and Mellors [16].

While the experimental procedures of Leonardi

and Brenet [21], Murgulescu and Sternberg [22].

and Salstrom [23] differ somewhat from Senderoff

and Mellors [16 1 it is apparent from table 1 that

the measurements are of a high quality.

5.1.2. Be | BeCL | Cl> | C.

[11,13,28,29,30,31,32]

The cell Be| BeCL | Cl2 1 C can not be measured

experimentally due to electronic conductivity of

the melt (Be metal dissolves in molten BeCl2 ) and

because of the high volatility of molten BeCl2 . Kuroda and Matsumoto [28 ] have measured cells

such as Be|BeCl2 , NaCl|Cl2 |C and have determined the E° value of this cell by an extrapolation

method. The extrapolation is unsatisfactory and

while uncertainties are introduced by combining

thermochemical E° values and experimental emfs,

this latter approach is recommended. The thermochemical data are unsatisfactory. Thus at 500 & C,

for example, the JANAF tables [13] list a value for

E

c as 1974 mV, while Sethi and Jindal [29] calculated

1844 mV, and Hamer, Malmberg, and Rubin [1 1

reported 2144 mV. Owing to the uncertainties in

E° the excess properties of BeCl2 containing mixtures are not calculated in the present work.

5.1.3. Cd|CdCl2 |Cl2 |C.

[11, 33, 34, 35, 36]

A complication in this system is the significant

solubility of Cd metal in molten CdCl2 . This influ- ences the emf of the cell and may also give rise to a junction potential. Electronic conductivity of

this cell has, however, not been reported; this may

be because the reaction of Cd metal with Cl2 near

the Cl2 1 C electrode completely depletes the melt near this electrode of dissolved Cd metal.

A reaction involving CdCl2 , Cl2 . and graphite has

been reported [33, 34] so that the selection of the

graphite for the C12 |C electrode in CdCl2 containing

melts must be made with care in order to minimize

this problem.

Lorenz and Velde [35] found an E° value which

is in good agreement with values reported by

Lantratov and Alabyshev [36] (table 3). Lantratov and Alabyshev [36] pretreated the C

electrode in a Cl2 atmosphere and separated the

molten Cd as much as possible from the bulk of

the melt. Their E° value at 600 °C is 1338 mV and

the thermochemical value [11] at 600 °C is 1331

mV; the difference may be due, in part, to thermoelectric effects.

5.1.4. (Ce,Sn)|CeCl3 |Cl2 |C. [37,39]

(Ce,Bi)|CeCl3 |Cl2 |C. [38]

Cerium metal has a significant solubility in molten

CeCl3 . The cells: (Ce,Sn)|CeCl3 (l —jc),KC1(jc) |

C

l 2 1

C

and Ce|CeCl3 (l — jc),KC1(jc) |C12 |C where x<^<\,

have been investigated by Senderoff, Mellors and

Bretz [37]. Whereas the emfs of the former were

stable, the emf data for the latter showed a continu- ous drift. The requirements for a suitable alloy

electrode, according to these investigators [37] are as

follows. The diluent metal of the alloy should be

very noble compared with cerium. The alloy should

consist of two phases over a considerable range of

composition to assure constant activity of Ce in

the heterogeneous alloy. The activity of cerium in

the alloy should be sufficiently low. The alloy must

behave electrochemically as a reversible Ce3+ |Ce& electrode. Senderoff, Mellors and Bretz [37] found

that these requirements were met in the cell

(Ce,Sn|CeCl3 |Cl2 |C.

The cell (Ce,Bi) | CeCl3 1 Cl2 | C has been investigated by Neil [38]. The composition of the alloy was determined after each experiment in order to calculate the activity of Ce in the Ce.Bi alloy.

5.1.5. Mg|MgCl2 |Cl2 |C. [35, 40, 11, 13]

(Mg, Bi) | MgCl2 1 Cl2 1 C. [38,41]

The cell Mg|MgCl2 |Cl2 |C has been measured by

means of the decomposition potential method by

Lorenz and Velde [35] and by Markov, Delimarskii

and Panchenko [40]. It should he noted that this

method does not assure equilibrium conditions;

a comparison of thermochemical values and the

“decomposition-potential E

° " for the present

system shows that the two values differ significantly (table 4). The appreciable solubility of Mg

metal in molten MgCL presents a further difficulty

for meaningful interpretations of the E° values.

The difficulties involved in the Mg|MgCl2 |Cl2 |C

cell were bypassed by Neil, Clark, and Wiswall

4
[38, 41] through the use of a magnesium alloy

electrode, e.g., (Mg, Bi)|MgCl2 1 Cl2 1 C; thermodynamic reversibility of the C12 |C electrode was also

investigated in this study. Varying alloy compositions were used and the p^gCl2 was calculated from

the measured cell emf and the activity of Mg in the

alloy (from the alloy composition data).

5.1.6. Mn| MnCl2 1 Cl2 1 C.

[11,42,43]

The cells Mn| MnCb, NaCl|Cl2 1 C and Mn|MnCl2 , KC1|C1>|C have been studied by Bruneaux, Ziolkiewicz and Morand [42, 43]. The E° of the systems

with *Mnci2 = l-0 was gained by extrapolation of

the data for the preceding cells for a range of compositions. While this “extrapolated £’°” is in good

agreement with the thermochemical value [11],

more information is needed before a reliable E°

value can be recommended. The use of Mn containing alloy electrodes should be considered in further

studies (c.f. Ce, Sn; Mg, Bi).

5.1.7. Pb|PbCl>|CL|C.

[11, 13, 35, 38, 44, 45, 46, 47, 48, 49, 50, 51,

52]

A comparison of the emf data for this cell re- ported by various investigators is in table 5. The

recent work of Hagemark and Hengstenberg [44] is probably the most accurate investigation. Up to 600 °C the Lantratov and Alabyshev [45] values

are in reasonable agreement with the Hagemark

and Hengstenberg [44] data. The difference between these two authors could be due to thermoelectric effects up to 600 °C. Hagemark and Hengstenberg [44] using a C12 |C electrode, nearly

identical to that of Senderoff and Mellors [16], took

care to minimize thermal emfs by using a graphite

electrode for the electrical contact with the molten

lead and investigated the influence of electrolysis on the emf. The purities of PbCl2 and Pb were also

checked and the observed emf values were cor- rected for fluctuations in the Cl2 pressure (the latter

corrections were less than 0.8 mV).

5.1.8. Pu|PuCU|Cl2 |C.

[53, 54]

Benz [53] and Benz and Leary [54] have studied

the cells: Pu | PuCL, KC1 1 Cl2 | C [53] and

Pu | PuCb, NaCl | Cl2 1 C [54]. The E° was calculated

by assuming regular solution theory for the binary

mixtures; this approach is not satisfactory. Unfortunately the properties of PuCL, e.g., the high melting

point of PuCb, its volatility, and the marked solubility of Pu metal in PuCL make a direct measure- ment of E° virtually impossible. The alloy electrode

technique should be explored in further investigation of PuCl3 mixtures.

5.1.9. Zn|ZnCl,|Cl,|C.

[11, 35, 50, 56, 57, 58, 59, 60, 61, 62]

A comparison of literature values for this cell is in table 6. Delimarskii and Markov [55] noted that

the finite vapor pressure of ZnCl2 decreases the

effective Cl2 pressure and that this results in values

of the emf that are too low. The Lorenz and Velde

values [35] were corrected accordingly by Delimarskii and Markov [55].

The most thorough investigation of this cell is that of Takahashi [56] in which the Cl2 pressure

corrections were undertaken on the assumption

that ZnCl2 and Cl2 do not interact in the vapor phase.

In this investigation ZnCl2 , which is extremely

hygroscopic, was dried and freed from oxide impurities, and finally electrolysed to remove traces

of moisture before the emf measurement. The re- sults of Takahashi [56] are the only ones which are

in good agreement with the thermochemical values

[11]. Takahashi [56] did not report a correction for

the thermal emf of the Zn|C couple; this correction

is undoubtedly small compared with the differences

between the various reported emfs.

5.1.10. Ag|AgBr|Br,|C.

[12, 63, 64, 65, 66, 67, 68]

Inspection of table 7 shows that the experimental

values of Salstrom and Hildebrand [63] and Murgulescu and Marchidan [64] are in good agreement

with the thermochemical data published by Hamer,

Malmberg and Rubin [12].

Salstrom and Hildebrand [63] used carefully dried

AgBr and established that electrolysis did not

change the cell emf. Corrections for variations of

the Br2 pressure and for thermoelectric effects were

also made in this study. Murgulescu and Marchidan

[64] pretreated the C electrode in a Br2 atmosphere

and by pre-electrolysis in molten AgBr. Most likely

the differences between reported values (table 7) are due to thermoelectric effects.

5.1.11. Cd | CdBr>| Br2 1 C.

[12, 69, 70]

There is only one investigation of this cell (Lantratov and Shevlyakova [69]) and the results have

been reported in the form of an equation. The uncertainties in this cell are the same as for the cell

Cd | CdCl2 1 Cl2 1 C. Salstrom [70] was unable to study

this cell Cd|CdBr2 |Br2 |C due to metal fog formation.

The difference between the experimental emf

[69] and the thermochemical values [12] (41 mV at 600 °C) makes further investigations of this cell desirable.

5.1.12. Pb|PbBr2 |Br2 |C.

[12, 13, 70, 71, 72, 73]

Inspection of table 9 shows that there is an

appreciable difference between the thermochemical

data for this cell [12, 13].

5
The most recent experimental investigation of

this cell is by Lantratov and Shevlyakova [71]. A

thin-walled graphite tube was used as the Br2 electrode, and this was saturated with Br2 and was

heated for 1.5 hr between 700 °C and 750 °C. The

E° values differ appreciably from the thermochemical values [12, 13] and from other experimental

values [70, 72].

Salstrom [70] and Salstrom and Hildebrand [72]

reported that equilibrium at the Br2 electrode was

established in 1 to 2 hr if the C rod electrode was

preheated in Br2 at several atmospheres pressure

and then heated in an oxygen flame. Without this

pretreatment, 18 to 20 hr were required before a stable emf was observed. These investigators

[70, 72] corrected for the thermoelectric emf using an empirically established factor. The difference

between the E° and the thermochemical value

may be, in part, due to this factor.

5.1.13.

Ag|AgI |I2 |C.

[12,74,75,76]

The only investigations on this system are those

of Sternberg, Adorian, and Galasiu [74, 75, 76].

The attainment of a reversible iodine electrode was

gained by keeping iodine in a gaseous state from

the moment of its generation up to its removal from

the cell. It was noted that the graphite had to be in

contact with iodine for 20 hr to establish stable potentials; this period could be reduced to 5 to 6 hr by

electrolysis. The reported E° values are corrected

for the thermoelectric effect at the Ag|C couple.

Table 10 shows that the agreement with thermochemical values is satisfactory.

5.1.14. Ag | AgN03 1 N02 ,02 1 Pt.

[4, 77, 78, 79, 80, 81]

The only investigation of this cell is that reported

by Ketelaar and Dammers-de Klerk [4, 77]. A threephase contact between the (N02 ,02 ) mixture, the

liquid nitrate, and platinum was found to be essential for measurements of thermodynamic signifi- cance. The results are in complete agreement with

th^ E° as calculated by the authors [77] from

thermochemical data [78, 79, 80, 81].

5.1.15. Cells with Glass as Cation Selective

Membranes.

[9, 10, 33, 34, 82, 83, 84]

The most complete investigations with this kind

of cell are those of Ostvold and Forland [9, 10, 82,

83]. Well defined types of glass were investigated for

cation-selective properties by transport measurements. It was also shown from theoretical considerations that thermodynamic results are possible from

such cells if the transport numbers through the glass are known. Dijkhuis and Ketelaar [33, 34, 85] and

Sternberg and Herdlicka [84], from indirect evidence, established that the electrical contact

through such glass membranes is by one kind of

ion only.

Thermochemical data of some “undercooled”

alkali halides are given in table 11; these are of

interest for cells with cation-selective glass

membranes.

5.2. Discussion of Individual Mixtures

1. (Ag,Li)Cl; 15. (Mg,Rb)Cl; 29. (Pu,Na)Cl; (Pu,K)Cl; 43. (Pb,K)Br;

2. (Ag,Na)Cl; 16. (Mn,Na)Cl, (Mn,K)Cl; 30. (Zn,Li)Cl; 44. (Pb,Zn)Br;

3. (Ag,K)Cl; 17. (Ca,Na)Cl; 31. (Zn,Na)Cl; 45. (Ag,K)I;

4. (Ag,Pb)Cl; 18. (Sr,Na)Cl; 32. (Zn,K)Cl; 46. (Cd,Na)I;

5. (Be,Na)Cl; 19. (Ba,Na)Cl; 33. (Zn,Rb)Cl; 47. (Pb,Na)I;

6. (Cd,Na)Cl; 20. (Pb,Li)Cl; 34. (Zn.Cs)Cl; 48. Ag(Br,Cl);

7. (Cd,K)Cl; 21. (Pb,Na)Cl; 35. (Zn,Ba)Cl; 49. Ag(I,Cl);

8. (Cd,Ba)Cl; 22. (Pb,K)Cl; 36. (Ag,Li)Br; 50. Ag(I,Br);

9. (Ce,Na)Cl; 23. (Pb,Rb)Cl; 37. (Ag,Na)Br; 51. K(Br,Cl);

10. (Ce,K)Cl; 24. (Pb,Cs)Cl; 38. (Ag,K)Br; 52. Na(Br.Cl);

11. (Ce,Ca)Cl; 25. (Pb,Ca)Cl; 39. (Ag,Rb)Br; 53. Pb(Br,Cl)

12. (Mg,Li)Cl; 26. (Pb,Sr)Cl; 40. (Ag,Pb)Br;

13. (Mg,Na)Cl; 27. (Pb.Ba)Cl; 41. (Cd,K)Br;

14. (Mg,K)Cl; 28. (Pb,Zn)Cl; 42. (Pb,Na)Br;

5.2.1. AgCl(l — x), LiCl(*).

Cells: Ag| AgCl,LiCl|Cl2 |C. [20,26]

Tables: 1, 12

Figure: la

Parameters for the excess free energy: a = 2.1 kcal/mol

b = 0.0 kcal/mol

c— 0.0 kcal/mol

Estimated uncertainty in 4C /

'; (.t= 0.5): 0.2 kcal/mol

Parameters for the excess entropy:

a' = 0.0 e.u.

b' = 0.0 e.u. c — 0.0 e.u. Estimated uncertainty in 4S£

(.* = 0.5) : 0.5 e.u. A comparison of the E° values of both authors

with the Senderoff and Mellors [16] values indicates

6
FIGURE 1. Experimental values of /x^

rC1/x2 and s^

KCI/x2 in molten binary chloride mixtures. The limits of uncertainty and the solid

lines are the result of the present analysis.

a. AgCl, LiCl

G Panish, Newton, Grimes, Blankenship [20], 800 °C

A Salstrom, Kew, Powell [26], 600 °C

b. AgCl, NaCl

O Panish, Blankenship, Grimes, Newton [19], 800 °C

Stern [25], 800 °C

A Sternberg and Gheorghiu [27], 800 °C

c. AgCl, KC1

A Murgulescu and Sternberg [22], 650 °C

Q Stern [24], 700 °C

d. AgCl, PbCl2 O Salstrom [23], 550 °C

7
a temperature limit of 800 °C for the Salstrom,

Kew and Powell [26] measurements, whereas the

Panish, Newton, Grimes, and Blankenship [20]

values are accurate even up to 900 °C. However,

the fact that extrapolated E° values are accurate

does not mean that the same holds for extrapolated

emfs of mixtures, especially when only a small

temperature range is investigated e.g. * = 0.864

[26]. Panish, Newton, Grimes, and Blankenship

[20] have covered the concentration range 0 x

0.9714, whereas Salstrom, Kew. and Powell [26]

investigated only lower melting mixtures (0 x

0.864).

Most experimental points reported by Salstrom,

Kew, and Powell [26] are included at 600 °C, whereas

the Panish, Newton, Grimes, and Blankenship data

[20] have a “best temperature range” from 650 to 800 °C. Although the values of Panish, Newton,

Grimes, and Blackenship [20] suggest some asymmetry (a =1.75 kcal/mol, 6 = 0.60 kcal/mol,

a' = —1.6 e.u., 6' = 2.6 e.u.) the recommended

values are gained from a combination of the data

of Panish, Newton, Grimes, and Blankenship [20]

and Salstrom, Kew, and Powell [26].

5.2.2.

AgCl(l-*),NaCl(*).

Cells: Ag|AgCl(l-*),NaCl(*)|Cl2 |C. [19,27,25]

Tables: 1, 13

Figure: lb

Parameters for the excess free energy: a = 0.8 kcal/mol

6= 0.0 kcal/mol

c = 0.0 kcal/mol

Estimated uncertainty in 46,£; (* = 0.5): 0.2 kcal/mol

Parameters for the excess entropy:

a' = 0.5 e.u.

b' = 0.0 e.u

c = 0.0 e.u.

Estimated uncertainty in 4S£ (*=0.5): 0.2 e.u.

The experimental difficulties for measuring cells

Ag|AgCl, NaCl|Cl2 |C are about the same as for

cells Ag|AgCl, LiCl | Cl2 |C (section 5.2.1). However,

it is easier to prepare a water-free AgCl,NaCl mixture than it is to make AgCl, LiCl water-free. It was found in section 5.1.1 that the E° values of

Panish, Blankenship, Grimes, and Newton [19, 20]

agree with the Senderoff and Mellors values [16].

The Sternberg and Gheorghiu [27] E° value is slightly different from the Senderoff and Mellors

values [16] which could partly be due to a different

correction for the thermoelectric effect of the Ag|C

couple. The Stern values [25] have appreciable

systematic errors. Panish, Blankenship, Grimes, and Newton [19]

investigated the concentration range 0 x =£ 0.9687

and have a “best-temperature range” from 750 to

800 °C. Sternberg and Gheorghiu [27] covered the

range 0 =Sjc^ 0.7 and have a “best-temperature”

of 800 °C.

Inspection of figure lb shows that there is a difference between values of Panish, Blankenship,

Grimes, and Newton [19] and Sternberg and

Gheorghiu [27] for small x, whereas the data of

Stern [25] deviate strongly from the other two

sets of data. The work of Panish, Blankenship,

Grimes, and Newton [19] indicates asymmetry in

GE and S

E (a = 0.78 kcal/mol, 6 = 0.27 kcal/mol,

c=0.0 kcal/mol, a' = 0.50 e.u., 6' = — 0.40 e.u.,

q' = 0.0 e.u.). However the recommended GE and

S

E values are an “average” of data reported by

Panish, Blankenship, Grimes, and Newton [19]

and Sternberg and Gheorghiu [27].

5.2.3. AgCl(l — x), KCl(ar).

Cells: Ag| AgCl, KC1| Cl2 1 C.

Tables: 1, 14

Figure: lc [24, 22]

Parameters for the excess free energy (650 °C): a = — 1.5 kcal/mol

6= 0.4 kcal/mol

c= 0.0 kcal/mol

Estimated uncertainty in 4GE (* = 0.5): 0.2 kcal/mol

From an experimental point of view the cell Ag|AgCl, KC1[CL|C is about the same as the

cell Ag| AgCl, NaCl| Cl2 1 C (section 5.2.2). For

reasons outlined in section 5.2.2 the recommended

excess values have been derived from emf data as published by Murgulescu and Sternberg [22].

These authors have only covered the concentration

range 0 0.65. The values nevertheless indicate an asymmetrical GE

(fig. lc). The s^gC1/*2 values

are too scattered to enable an estimate of S

E .

5.2.4. AgCl(l-*), PbCl2 (*)

Cells: Ag|AgCl, PbCl2 |Cl2 |C.

Tables: 1, 15

Figure: Id [23]

Parameters for the excess free energy (550 °C): a = — 0. 15 kcal/ mol

6= 0.20 kcal/mol

c — 0.00 kcal/mol

Estimated uncertainty in 4GE

(* = 0.5): 0.05 kcal/mol

Parameters for the excess entropy (550 °C):

a' = — 0.9 e.u 6'= 0.8 e.u. c'= 0.0 e.u.

Estimated uncertainty in TS*'- (* = 0.5): 0.1 e.u. From an intercomparison of E° values (section

5.1.1) it follows that there are no systematic errors

I
involved in the E° values of Salstrom [23, 26].

Salstrom [23] freed the mixture from moisture

and oxidation and hydrolysis products by bubbling

dry hydrogen chloride through the melt. He covered

the concentration range 0 x ^ 0.9. Inspection of

figure Id shows that it is most likely that the reaction

2Ag+ Pb2+ —

>

2Ag+ + Pb has not influenced the

cell emf.

5.2.5. BeCl2 (l-x), NaCl(x).

Cells: Be|BeCl2 ,NaCl|Cl2 |C.

Table: 2 [29,28,30,31,32]

It was pointed out in section 5.1.2 that although

the cells Be|BeCl2 , NaCl|Cl2 |C have been measured under equilibrium conditions, GE values will

not be reported due to difficulties involved in obtaining reliable E° values.

5.2.6. CdCl2 (l -x), NaCl(x).

Cells: Cd| CdCl2 (l — x), NaCl(x)| Cl2 | C. [36]

W|Cd|CdCl2,NaCl|glass|CdCl2 ,NaCl|Cd|W

(1-x) (x) (0.6) (0.4)

[33, 34]

Tables: 3, 16

Figure: 2a

Parameters for the excess free energy (600 °C): a = — 4.45 kcal/mol

b = — 3.85 kcal/mol

c= 0.00 kcal/mol

Estimated uncertainty in 4Gf; (x=0.5) 0.1 kcal/mol

The excess free energy as determined from cell

Cd| CdCl2 1 Cl2 1 C has an uncertainty due to Cd metal

solubility in the melt (section 5.1.3). It can be seen from figure 2a that according to Lantratov and

Alabyshev [36] the GE of CdCl2 , NaCl mixtures has

a high value for the parameter c which is not very

probable when one compares the mixture CdCl2 , NaCl with the mixture CdCl2 , KC1 (section 5.2.7).

Lantratov and Alabyshev [36] find extremely negative and extremely asymmetrical values for the excess entropy (table 16).

Knowledge of E° values is not required for the

calculation of the excess properties from cells in

which glass functions as a cation-selective membrane [33, 34]. Dijkhuis and Ketelaar [33, 34] give

indirect evidence that electrical transport through

glass in the cell W|Cd|CdCl2 , NaCl| glass] CdCl2 , NaCl|Cd|W is only by sodium ions, and calculate

the excess properties accordingly.

5.2.7. CdCI2 (l — x), KCl(x).

Cells: Cd|CdCl2 (l —x), KCl(x)|Cl2 |C. [36]

Tables: 3, 17

Figure: 2b

Parameters for the excess free energy (600 °C): a = —7.5 kcal/mol

6 = — 10.7 kcal/mol

c = 0.0 kcal/mol

Estimated uncertainty in 4G£ (x = 0.5) 0.5 kcal/mol

The uncertainties involved in deriving excess

properties from cells Cd|CdCl2 , NaCl|Cl2 |C have

been discussed in sections 5.1.3 and 5.2.6: cells

Cd|CdCl2 , KC1 1 Cl2 1 C have been studied by Lantratov and Alabyshev [36]. However, while /x E

dc[ Jx2 versus x values derived from cells Cd|CdCl2 , NaCl|Cl2 |C show appreciable curvature, the

lx2 versus x plot as derived from cells

Cd|CdCl2 , KC1| Cl2 1 C gives a straight line relationship. This could be due to the fact that the absolute

value of GE

is higher for the mixture CdCl2 , KC1 than

for the mixture CdCl2 , NaCl which means that

experimental errors have a relatively smaller influ- ence for the former mixture. However, the excess

entropies as determined from cells Cd|CdCl2 , KC1| Cl2 1 C seem to be too high (a' = —10 e.u.,

6' = 0 e.u., c' = 0 e.u., estimated uncertainty in

4S£(x = 0.5)=5 e.u.).

5.2.8. CdCl2 (l — x), BaCl2 (x).

Cells: Cd|CdCl2 , BaCl2 |Cl2 |C. [36]

Tables: 3, 18

Figure: 2c

Parameters for the excess free energy (600 °C): a = — 1.0 kcal/mol

6 = — 8.8 kcal/mol

c = 0.0 kcal/mol

Estimated uncertainty in 4G£ (x= 0.5): 0.5 kcal/mol

Some uncertainties involved in CdCl2 containing

formation cells have been outlined in sections 5.1.3,

5.2.6, and 5.2.7. Special difficulties resulting from

properties of BaCl2 have not been reported by

Lantratov and Alabyshev [36]. Inspection of figure

2c shows a straight line relationship between

Mcac\Jx

~ versus x and s E

acJx2 versus x. This gives

some indication about the S

E values (a' = — 9.0 e.u., b'= — 8.5 e.u.; estimated uncertainty in 4S£ {x = 0.5): 1.0 e.u.).

5.2.9. CeCl3 (l — x), NaCl(x).

Cells: (Ce, Sn)| CeCLU ~x) , NaCl(x) |C12 |C. [37]

Table: 19

Figure: 3a

Parameters for the excess free energy (800 °C): a = —2.7 kcal/mol

b = —13.6 kcal/mol

c = 9.3 kcal/mol

Estimated uncertainty in 4G£ (x = 0.5): 0.4 kcal/mol

9
FIGURE 2. Experimental values of p.ECdClJx

2 and s cdci^x2 molten binary chloride mixtures. The limits of uncertainty

and the solid lines are the result of the present analysis.

a. CdCl2 , NaCl

O Lantratov and Alabyshev [36], 600 °C — Dijkhuis and Ketelaar [33, 34], 600 °C

b. CdCl2 , KC1

O Lantratov and Alabyshev [36], 600 °C •

c. CdCl2 , BaCl2 O Lantratov and Alabyshev [36], 600 °C

10
Figure 3. Experimental values of pfeC^

I x2 and ^?eC1) l x

*

* n molten binary chloride mixtures. The solid lines are the results of the present

analysis.

a. CeCk, NaCl

I G Senderoff, Mellors, Bretz [37], 800 °C

b. CeCl3 , KC1

O Senderoff, Mellors, Bretz [37], 850 °C

A Neil [38], 850 °C

c. CeCl3 , CaCl2 Q Senderoff, Mellors, Bretz [39], 850°C

It was outlined in section 5.1.4 that Senderoff,

Mellors, and Bretz [37] investigated the reversibility of this cell. Emf data have only been reported

at three temperatures (800 °C, 850 °C, and 900 °C).

This means that random errors could not be

calculated.

The /x£eC i :i /-t 2 versus x plot (fig. 3a) shows a curvature which indicates that the parameter c has an

appreciable value when compared with the parameters a and b. The 5ceciJ

%2 versus x plot also suggests some

curvature; however, the scatter of the data allows

only a rough estimate of S

E (a' = — 8 e.u., b' = 0 e.u. and c' — 0 e.u.).

5.2.10. CeCl3(l — *), KCl(ar).

Cells: (Ce,Sn)|CeCl3 , KC1|C12 |C. [37]

(Ce,Bi)|CeCl3 , KC1|C12 |C. [38]

Table: 20

Figure: 3b

Parameters for the excess free energy (850 °C): a = — 1.87 kcal/mol

b = — 31.75 kcal/mol

c= 20.48 kcal/mol

Estimated uncertainty in 4G£ (x :=: 0.5): 0.4 kcal/mol

335-493 0-69—2 11
The comparison of excess properties as derived

from the two cells provides a means of comparing

the alloy electrodes. Table 20 and figure 3b show

clearly that the values from the (Ce, Bi) electrode

deviate strongly from those derived from the (Ce, Sn)

electrode. Neil [38] has calculated the activity of

Ce in the alloy from the alloy composition, whereas

Senderoff, Mellors, and Bretz [37] worked with a constant alloy composition. For this reason the

Senderoff, Mellors, and Bretz values are recom- mended. The plot of sE

eCJx2 versus x as derived

from measurements of Senderoff, Mellors, and

Bretz [37] suggests asymmetry. However, S

E values can only be estimated (a = — 10.8 e.u., b' = 28.4

e.u., c'= — 29.6 e.u.; estimated uncertainty in

4S£ (x = 0.5): 2 e.u.) due to the scatter of the experimental points.

5.2.11. CeCl3(l -x), CaCl2(*).

Cells: (Ce,Sn)|CeCh,CaCl2 |Cl,|C [39]

Table: 21

Figure: 3c

Parameters for the excess free energy (850 °C): a = 4.80 kcal/mol

b = — 8.79 kcal/mol

c— 5.37 kcal/mol

Estimated uncertainty in 4GE

(* = 0.5): 0.5 kcal/mol

Parameters for the excess entropy (850 °C):

a' = — 20.6 e.u.

b'

43.8 e.u.

c' = — 29.2 e.u.

Estimated uncertainty in 4S£ (*=0.5): 2 e.u. The experimental arrangement was the same as

for cells containing CeCl3 , NaCl (section 5.2.9)

and CeCl3 , KC1 (section 5.2.10). Special care was

taken to avoid impurities in the CaCl2 . Figure 3c shows clearly that both GE and S

E are asymmetrical in normal mole fractions. The continuity in plots of p,ceCl! /x 2 versus * and s E

eClJx 2 versus * indicates small random errors.

5.2.12. MgCl2(l -jc), LiCl(*).

Cells: Mg|MgCl2 (l — *), LiCl(*)|Cl2 |C. [40]

Tables: 4,22

Figure: 4a

Parameters for the excess free energy (700 °C):

a— 3.95 kcal/mol

b = — 5.75 kcal/mol

c = 0.00 kcal/mol

Estimated uncertainty in 4GE (*=0.5): 0.5 kcal/mol

The recommended values might have an even

higher systematic error than is indicated above, due

to the fact that the decomposition-potential method

(i — V) was used. This is not an equilibrium measurement. The excess entropy of this mixture (a' = 26.5

e.u., 6'=— 17.5 e.u., c' = 0.0 e.u.) seems to be too

high. This could indicate that appreciable systematic

errors are involved in the Markov, Delimarskii, and

Panchenko data [40].

5.2.13. MgCl2(l —*), NaCl(x).

Cells: Mg|MgCl2 , NaCl|Cl2 |C. [40]

(Mg, Bi)|MgCl», NaCl|Cl-|C. [38, 41]

C|Cl2 |NaCl|glass|MgCl2 , NaCl|Cl2 |C. [9]

Tables: 4, 23

Figures: 4b, 4b'

Parameters for the excess free energy: a = —4.80 kcal/mol

b — ~ 9.39 kcal/mol

c — 7.08 kcal/mol

Estimated uncertainty in 4GE

(* = 0.5): 0.5 kcal/mol

Parameters for the excess entropy (850 °C):

a' = — 1.2 e.u.

6' = 0.0 e.u.

c' = 0.0 e.u.

The ju,^gCl2 values of the mixture can be calculated

from the cells Mg|MgCl2 , NaCl|Cl2 |C [40] and

(Mg, Bi)|MgCl2 , NaCl|Cl2 |C [38, 41] whereas

P-Naci val ues are measured in cells C|Cl2 |NaCl|

glass|MgCl2 , NaCl|Cl2 |C [9]. Markov, Delimarskii,

and Panchenko [40] used a nonequilibrium type cell

(section 5.2.12) whereas the cell with the alloy

electrode (Neil, Clark and Wiswall [38, 41]) is in

principle an equilibrium measurement.

Inspection of figure 4b shows a curvature in

/u-Mgc

2 /* 2 versus * according to Neil, Clark and

Wiswall [41]. (a = — 4.15 kcal/mol, b = —14.18

kcal/mol, c= 11.09 kcal/mol.) In this study data

have been determined at 825 °C only. This means

that excess entropies cannot be calculated from the

temperature dependence of these emf data.

Ostvold [9] has determined /u^aC1 values by means

of emf measurements on cells in which glass functions as a sodium ion selective membrane (section

5.1.15). These values are presented in figure 4b'.

Although this plot shows a curvature (a = — 2.58

kcal/mol, 6 = —13.26 kcal/mol, c=9.13 kcal/mol),

the scatter of points around the composition * = 0.5

makes a quantitative estimate uncertain.

From experimental consideration it follows that

the Ostvold values [9] are most accurate on the NaCl

side of the system, whereas the Neil, Clark, and

Wiswall values [41] are most accurate on the MgCl2 side. The recommended values were determined by

appropriate weighing of the two sets of data.

Figure 4b' shows that the excess entropy, as determined by Ostvold [9], has an appreciable ran- dom error. These data are suitable for an estimate

12
FIGURE 4. Experimental values of P-^Jx2

( or /iJfaCI/(l — x)2

) and s^bC)2/x2 (or s§aC] l(\ — xf) in molten binary chloride mixtures con- taining MgCL. The limits of uncertainty and the solid lines are the result of the present analysis.

a. MgCl>, LiCl

0 Markov, Delimarskii and Panchenko [40], 700 °C

'b. MgCl-2 , NaCl

© Markov, Delimarskii, Panchenko [40], 700 °C

A Neil, Clark, Wiswall [41], 825 °C

b'. MgCl-2 , NaCl

O Ost void [9], 850 °C

c. MgCl2 , KC1

A Markov, Delimarskii, Panchenko [40], 700 °C

0 Neil, Clark, Wiswall [41], 800 °C

d. MgCl2 , RbCl

© Markov, Delimarskii, and Panchenko [40], 700 °C

13
of the excess entropy (a

1 = — 1 e.u., b' = c' = 0 e.u.).

It is seen that the excess entropy of the mixture

MgCl2 , NaCl has a small influence on the total excess free energy.

Parameters for the excess free energy (850 °C): a = — 2.45 kcal/mol

b = — 0.45 kcal/mol

c— 0.0 kcal/mol

5.2.14. MgCI2(l —*), KCl(x).

Cells: Mg|MgCl2 (l — x), KC1(x)|C12 |C. [40]

(Mg, Bi)|MgCl2 (l —*), KC1(*)]C12 |C. [38, 41]

Tables: 4, 24

Figure: 4c

Parameters for the excess free energy (800 °C): a = —12.84 kcal/mol

b = —11.88 kcal/mol

c= 12.96 kcal/mol

Estimated uncertainty in 4GE (x = 0.5): 0.9 kcal/mol

The cells have been discussed in section 5.2.13.

It was pointed out in that section that due to non- equilibrium conditions unacceptable uncertainties

are involved in the kind of cell investigated by

Markov, Delimarskii, and Panchenko [40]. The

recommended values were calculated from the cell

of Neil, Clark, and Wiswall [41]. The latter authors

published their values at one temperature only and

the excess entropies can therefore not be calculated.

5.2.15. MgCl2(l —*), RbCl(x).

Cells: Mg|MgCl2 , RbCl|Cl2 |C. [40]

Table: 25

Figure: 4d

This mixture has been investigated by a non- equilibrium method. One can expect to get only

some order of magnitude for the excess free energy

from this kind of cell: a = —11.5 kcal/mol,

b = — 20.5 kcal/mol. The cell used by Markov,

Delimarskii, and Panchenko [40] was discussed in

section 5.2.13.

5.2.16. MnCl2 , NaCl and MnCl2, KC1.

Cells: Mn MnCl2 , NaCl|Cl2 |C. [42,43]

Mn MnCl2 , KC1|C12 |C. [42 , 43]

These cells have been discussed in section 5.1.6. As the E

c value of this cell is uncertain it was

decided not to recommend excess properties for

these mixtures.

5.2.17. CaCl2(l —*), NaCl(jc).

Estimated uncertainty in 4GE (jc = 0.5): 0.5 kcal/mol

Parameters for the excess entropy (850 °C): a =— 1.75 e.u.

b’ = 3.39 e.u.

c' = — 3.68 e.u.

Estimated uncertainty in 4S £

(x = 0.5): 0.4 e.u.

The use of glass as a cation-selective membrane

is discussed in section 5.1.15. Ostvold [9] found that

electrical transport through glass was by means of

sodium ions only. This author bubbled dry hydrogen

chloride through the melt for 2 to 5 hr in order to remove hydroxides.

Inspection of figure 5a shows a curvature in the

P-Naci /(I ~x) 2 versus x plot. However, this curvature

depends strongly on mixtures dilute in NaCl or mixtures dilute in CaCl2 . A straight line relationship

is recommended. The s$aCl l(l—x) 2 versus x plot

shows a curvature and the S

E values are recom- mended accordingly.

5.2.18. SrCl^l -*), NaCl(*).

Cells: C | Cl2 1 NaCl | glass | SrCl-2 (l — jc), [9] NaCl(*)|Cl2 |C.

Table: 27

Figure: 5b

Parameters for the excess free energy (850 °C): a = — 0.02 kcal/mol

6 = —1.92 kcal/mol

c= 1.03 kcal/mol

Estimated uncertainty in 4GE

(x = 0.5): 0.5 kcal/mol

Parameters for the excess entropy (850 °C):

a' = — 0.81 e.u. 6'= 2.08 e.u.

c' =— 1.73 e.u. Estimated uncertainty in 4S

E

(* = 0.5): 0.4 e.u. The experimental procedure was the same as for

the mixture CaCl2 , NaCl (section 5.2.17). Inspection

of figure 5b shows clearly a curvature in both the

/x^aCi/(l —*) 2 versus * and s E

aC] j(\— x) 2 versus x. versus * plot. The parameters for the excess free

energy and for the excess entropy have been calculated, accordingly, from the Ostvold data [9]. 5.2.19. BaCl2(l -jc), NaCl(x).

Cells: C|Cl2 |NaCl glass |CaCl2 (l —*),

NaCl(*)|Cl2 C.

Table: 26

Figure: 5a

[9] Cells: C|Cl2 |NaCl|glass|BaCl2 (l -*),

NaCl(*)|Cl2 |C.

Table: 28

Figure: 5c

[9]

14
a>

4) o

Parameters for the excess free energy (850 °C):

a— 0.08 kcal/mol

b = — 0.04 kcal/mol

c— 0.00 kcal/mol

Estimated uncertainty in 4GE

(jc = 0.5): 0.1 kcal/mol

Parameters for the excess entropy (850 °C):

a' — 0. 14 e.u.

b' = 0.07 e.u.

c' = 0.00 e.u.

Estimated uncertainty in 4S

E (x=0.5): 0.05 e.u.

0 0 0.5 10

x

Figure 5. Experimental values for ( 1 — x) 2 and n/ ( 1 — x) 2

in binary alkaline earth chloride-sodium chloride mixtures. The

solid lines are the result oj the present analysis.

a. CaCI>, NaCI

© Ost void [9], 850 °C

b. SrCb, NaCI

© Ost void [9], 850 °C

o. BaCI,, NaCI

© Ostvold [9], 850 °C

The cell has been discussed in section 5.2.17.

Inspection of figure 5c suggests curvature for both

/^Naci/O — x ) 2 versus x and SnaCJ(l—xf ! versus x. However, it was decided that the curvature was not

pronounced enough and straight line relationships are recommended.

5.2.20. PbCl2 (l -*), UC1(*).

Cells: Pb|PbCl2 ,LiCl|Cl,|C. [45,46]

Tables: 5, 29

Figure: 6a

Parameters for the excess free energy (600 °C): a — 0.45 kcal/mol

b = — 0.55 kcal/mol

c = 0.00 kcal/mol

Estimated uncertainty in 4G£ (^=0.5): 0.2 kcal/mol

Lantratov and Alabyshev [45] have investigated

the cell under equilibrium conditions. Inspection

of table 7.1.7a shows at 600 °C a difference of

5 mV between the E° values of Hagemark and

Hengstenberg [44] and Lantratov and Alabyshev

[45]. This difference could be due to thermoelectric

effects. Lantratov and Alabyshev [45] do not report

special precautions in handling LiCl.

Markov, Delimarskii and Panchenko [46] have

used the decomposition potential method. For this

15
<DO

u

JC

(SI

</)

0)

0.0 0.5 10 0.0 05 10 V X

FIGURE 6. Experimental values for .p. £b( /x2 and s

pw:i A2 tn binary chloride mixtures. The limits of uncertainty and the solid lines are the result of the jiresent analysis.

a. PbCl2 , LiCI

A Markov, Delimarskii, Panchenko [46], 600 °C

© Lantratov, Alabyshev [45], 600 °C

b. PbCl2 , NaCl

V Markov, Delimarskii. Panchenko [46], 600 °C

A Lantratov. Alabvshev [45], 600 °C

© Suskii [48], 600 °c Hagemark, Hengstenberg [44], 600 °C

Dijkhuis, Ketelaar [33, 34], 600 °C

c. PbCl2 , KC1

© Hildebrand and Ruhle [49], 600 °C

A Lantratov and Alabyshev [45], 600 °C

El Markov, Delimarskii, Panchenko [46], 600 °C

V Hagemark and Hengstenberg [44], 600 °C

reason the recommended free energy data have

been calculated from the Lantratov and Alabyshev

[45] equilibrium data. The three points (fig. 6a) give

a perfect linear relation between fXpbclJx2 and x. Although the random error in these measurements

d. PbCl2 , RbCl

© Markov. Delimarskii, Panchenko [46], 600 °C

e. PbCl2 , ZnCl2 © Wachter, Hildebrand [50], 500 °C

A Nakamura and Brenet [51], 500 °C

is quite high, an asymmetrical excess free energy

is recommended. The temperature dependence of

data reported by Lantratov and Alabyshev [45]

does not give much information about the excess entropy of this mixture.

16
5.2.21. PbCl2 (l - *), NaCl(*).

Cells: Pb|PbCl2 , NaCl|Cl2 |C. [44.45.46,48]

W|Pb|PbCL>, NaCl|glass|PbCl2 (* = 0.6),

NaCl(* = 0.4)|Pb|W. [33,34]

Tables: 5, 30

Figure: 6b

Parameters for the excess free energy (600 °C): a = — 1.52 keal/mol

b = — 0.39 kcal/mol

c = 0.00 keal/mol

Estimated uncertainty in 46

' h (* = 0.5): 0.2 kcal mol

The Mpbc\Jx2 versus * data, as determined by var- ious authors are presented in figure 6b. Equilibrium

cells: e.g., Pb|PbCl2 , NaCl|Cl2 |C have been investigated by Lantratov and Alabyshev [45] and by

Hagemark and Hengstenberg [44]. By combining

these two sets of data the mixture PbCl2 , NaCl

turns out to be regular with a value of the a parameter of — 1 kcal/mol ±0.5 kcal/mol.

Dijkhuis and Ketelaar [33, 34] used a cell in which

glass functions as a cation-selective membrane

(section 5.1.15). As these authors did not have to subtract large quantities in order to find a small

difference these values are recommended.

Inspection of figure 6b shows that the Markov,

Delimarskii and Panchenko values [46], which were

determined by a nonequilibrium technique, do not

agree with the equilibrium values.

The SpbCl2 /*2 values as determined from the temperature dependence of emfs of equilibrium cells

have too much scatter to allow the derivation of excess entropies (table 30).

5.2.22. PbCI2 (l -*), KCI(*).

Cells: Pb|PbCl2 , KC1|C12 |C. [44,45,46,49]

Tables: 5, 31

Figure: 6c

Parameters for the excess free energy (600 °C): a = — 5.0 kcal/mol

b = 0.0 kcal/mol

c = 0.0 kcal/mol

Estimated uncertainty in 4GE

(* = 0.5): 1.0 kcal/mol

Parameters for the excess entropy (600 °C):

a' = — 2.0 e.u.

b' = 18.0 e.u.

c' = 0.0 e.u.

Estimated uncertainty in 4S

E (*=0.5): 1.0 e.u.

The Mpbcu/*

2 data of this mixture as determined

by various authors have been plotted versus * in

figure 6c. Hildebrand and Ruhle [49] used a nonequilibrium technique and find values that deviate

strongly from the data determined by means of

equilibrium measurements. However, it is remarkable that Markov, Delimarskii, and Panchenko [46]

who also used a nonequilibrium method find values

that are in good agreement with the equilibrium

data.

The data of Hagemark and Hengstenberg [44]

suggest some asymmetry in the excess free energy.

However, the recommended values for the excess

free energy were determined by combining the

equilibrium data reported by Hagemark and

Hengstenberg [44] and by Lantratov and Alabyshev

[45].

The temperature dependence of the emfs of

formation cells gives rise to a strongly asymmetrical

excess entropy. This asymmetry follows from the

data of Lantratov and Alabyshev [45] and Hagemark

and Hengstenberg [44] (see fig. 6c).

5.2.23.

PbCl 2(l -*), RbCI(*).

Cells: Pb|PbCl2 , RbCl|Cl2 |C. [46]

Tables: 5, 32

Figure: 6d

Parameters for the excess free energy (600 °C): a = — 6.5 kcal/mol

6 = — 0.1 kcal/mol

c= 0.0 kcal/mol

Estimated uncertainty in 4GE

(* = 0.5): 1.0 kcal/mol

This mixture has only been investigated by means

of the nonequilibrium technique of Markov, Delimarskii, and Panchenko [46]. The recommended

values have to be considered as an order of

magnitude.

5.2.24 PbCl2(l —*), CsCl(*).

Cells: Pb|PbCl2 , CsCl | Cl2 1 C. [44]

Tables: 5, 33

Parameters for the excess free energy (650 °C): a = — 7.3 kcal/mol

b = — 5.2 kcal/mol

c — 0.0 kcal/mol

Estimated uncertainty in 4GE

(* = 0.5): 0.5 kcal/mol

This mixture was investigated by an equilibrium

method. However, Hagemark and Hengstenberg

[44] only investigated two compositions. The recom- mended values have been derived under the as- sumption that the parameter c is zero. The excess entropies determined by Hagemark

and Hengstenberg [44] seem to be too high. It is interesting to note that according to Hagemark and

Hengstenberg [44] the excess entropy is given by

a' = 10.8 e.u., b' — — 12.3 e.u., c' = 0.0 e.u.: this

implies that the excess entropy is positive at the

PbCl2 side of the system, and becomes negative

at the CsCl side.

17
5.2.25. PbCl2 (l -*), CaCh(x).

Cells: Pb|PbCl2 , CaCl2 |Cl2 |C. [45]

Tables: 5, 34

Parameters for the excess free energy (650 °C): a — 0.6 kcal/mol

b = — 2.8 kcal/mol

c = 0.0 kcal/mol

Estimated uncertainty in 4GE (.t = 0.5): 0.5 kcal/mol

Lantratov and Alabyshev [45] used an equilibrium method for the investigation of this mixture.

Only two compositions were studied. The recom- mended parameters have been determined with the

assumption that the parameter c is zero.

5.2.26. PbCl2 (l — at), SrCl2 (ar).

Cells: Pb|PbCl2 , SrCl2 |Cl2 |C. [45]

Tables: 5, 35

Parameters for the excess free energy (650 °C):

a = 1.3 kcal/mol

b = — 1.6 kcal/mol

c= 0.0 kcal/mol

Estimated uncertainty in 4G E 6=0.5): 0.4 kcal/mol

Lantratov and Alabyshev [45] used an equilibrium method for the investigation of this mixture;

only two compositions were studied. The recom- mended parameters have been determined with

the assumption that the parameter c is zero.

5.2.27. PbCl2 (l - *), BaCl2 (*).

Cells: Pb|PbCl2 , BaCl2 |Cl2 |C. [45]

Tables: 5, 36

Parameters for the excess free energy (650 °C): a = — 0.7 kcal/mol

6 = — 3.0 kcal/mol

c— 0.0 kcal/mol

Estimated uncertainty in 46’ E (.t=0.5): 0.2 kcal/mol

Lantratov and Alabyshev [45] used an equilibrium cell for the investigation of this mixture;

only two compositions were studied. The recom- mended values have been determined with the

assumption that the parameter c is zero.

5.2.28 PbCl2 (l -jc), ZnCl2 (*).

Cells: Pb|PbCl2 ,ZnCl2 |Cl2 |C. [50]

C|Cl2 |PbCl2 |Pb|PbCl2 (l-x),

ZnCl2 (*)(Cl2 |C. [51]

Tables: 5, 37

Figure: 6e

Parameters for the excess free energy: a = — 1.65 kcal/mol

b = 1.15 kcal/mol

c = 0.00 kcal/mol

Estimated uncertainty in 4GE

(jc = 0.5) 0.2 kcal/mol

Wachter and Hildebrand [50] and Nakamura and

Brenet [51] have worked with equilibrium cells. The two cells are essentially the same. However,

the cell of Nakamura and Brenet [51] has the advantage that E° and E are already subtracted in

the actual measurement and the recommended

values for the excess free energy were determined

from the data of this study accordingly. The values

of Wachter and Hildebrand [50] differ slightly from

these values (fig. 6e).

The excess entropy has been estimated from the

data of Wachter and Hildebrand [50]. The data in the

5 Pbc\J%2 versus x plot are scattered. A reasonable

estimate for the excess entropy of this mixture is a' = 1.5 e.u. and b' = c' = 0.0 e.u., with an uncertainty estimate of 0.5 e.u.

5.2.29. PuCl3 (l -jc), NaCl(jt), and

PuCl3 (l —*), KC1(*).

Cells: Pu PuCl3 , NaCl|Cl2 |C. [54]

Pu PuCl3 , KC1|C12 |C. [53]

These cells have been measured by Benz and

Leary [54] and by Benz [53]. Due to the high melting

point of PuCL the cell Pu|PuCl3 |Cl2 |C could not be

measured and the method used by Benz and

Leary [54] and by Benz [53] for the determination of

the E° is questionable. Excess properties for the

mixtures mentioned above have therefore not been

calculated.

5.2.30. ZnCl2 (l -*), LiCl(ar).

Cells: Zn|ZnCl2 , LiCl | Cl2 1 C. [58]

Tables: 6, 38

Figure: 7a

Parameters for the excess free energy (550 °C): a = 2.9 kcal/mol

6 = — 1.3 kcal/mol

c— 0.0 kcal/mol

Estimated uncertainty in 4GE

(jt = 0.5): 1.5 kcal/mol

Markov and Volkov [58] have measured this cell by means of the decomposition potential method

(nonequilibrium method). Table 6 shows that their

E° values deviate strongly from the E° values obtained by equilibrium methods.

The excess free energy of the mixture ZnCl2 , LiCl has been determined from the Markov and

Volkov [58] data under the assumption that cancellation errors is most probable at the ZnCl2 side of the

18
5

FIGURE 7. Experimental values of Mzn ci2 / x2 and s£nC, 2 /x2 in molten binary chloride mixtures. The limits of uncertainty and the solid lines are the result of the present analysis.

a. ZnCl2 , LiCl

© Markov and Volkov [58], 550 °C

b. ZnCl2 , NaCl

© Lantratov, Alabyshev [59]

Dijkhuis, Ketelaar [85]

c. ZnCl2 , KC1

© Markov, Volkov [60],

A Lantratov, Alabyshev [59]

system. The recommended data are no better than

an order of magnitude.

5.2.31. ZnCl2 (l -jc), NaCl(jc).

Cells: Zn|ZnCl2 , NaCl|Cl2 |C. [59]

W|Zn|ZnCl2 , NaCl | glass |ZnCl>(;c = 0.6),

NaCl(* = 0.4)|Zn|W. [85]

Tables: 6, 39

Figure: 7b

Parameters for the excess free energy (600 °C): a = — 4.37 kcal/mol

b = — 5.54 kcal/mol

c= 0.00 kcal/mol

Estimated uncertainty in 4GE

(a: = 0.5): 0.4 kcal/mol

Difficulties involved in measuring the equibbrium

cell Zn|ZnCl2 |Cl2 |C have been discussed in section

5.1.9. It has to be concluded from this discussion

19
that appreciable systematic errors are involved in

the excess properties as derived from the Lantratov

and Alabyshev [59] data.

Dijkhuis and Ketelaar [85] have bypassed some

of the experimental difficulties involved in ZnCl2 formation cells by using glass as a cation selective

membrane (sec. 5.1.15).

In such cells the mixture was completely closed

to the atmosphere; the use of the CI2 1 C electrode

was unnecessary so that the vapor pressure of the

mixtures did not influence the emfs.

Inspection of figure 7b shows that the values

determined from the formation cells [59] and those

from cells with glass as a cation selective membrane

are in good agreement. It would appear that some

fortunate cancellations of errors occurs in the

studies with the formation cells [59].

5.2.32. ZnCl2 (l - *), KC1(*).

Cells: Zn|ZnCl2 , KC1|C12 |C. [60] Nonequilibrium

Zn|ZnCl2 , KC1|C12 |C. [59] Equilibrium.

Tables: 6, 40

Figure: 7c

Parameters for the excess free energy (550 °C): a = — 10 kcal/mol

6 = — 18 kcal/mol

c— 0 kcal/mol

Estimated uncertainty in 4GE

(* = 0.5): 2 kcal/mol

The two kinds of cells have already been discussed in sections 5.2.30 and 5.2.31. It was noted

that while appreciable systematic errors are present

in these studies, the excess properties, derived

from these two different kinds of cells are in reasonable agreement.

The recommended values for the excess free

energy have been calculated from the equilibrium

data of Lantratov and Alabyshev [59].

5.2.33. ZnCl2 (l —#), RbCl(*).

Cells: Zn|ZnCl2 , RbCl|Cl2 |C. [60, 61]

Tables: 6, 41

These systems have been studied only by a nonequilibrium technique (Markov and Volkov [60]

and Markov [61]). The excess free energy has been

estimated from the most recent data [60]. The re- sults, graphed as /x EnChlx2 versus *, are quite scat- tered. The estimated values of the parameters

a and b are at 550 °C: a = —19 kcal/mol; 6 = —

9

kcal/mol, c = 0 kcal/mol. The uncertainty in these

parameters may be as high as 5 kcal/mol.

5.2.34. ZnCl2 (l — #), CsCI(jc).

Cells: Zn|ZnCl2 , CsCl|Cl2 |C. [62]

Tables: 6, 42

Markov and Volkov [62] investigated this mixture

by a nonequilibrium technique. The errors involved

are appreciable in this method and have been discussed in preceding sections (5.2.32, 5.2.33). The

results, in the AtfnCl2 /*2 versus x plot, are too scat- tered to enable an accurate determination of the excess free energy. By assuming regular solution

behavior, the order of magnitude of the excess

free energy is approximated as: a = — 15 kcal/mol

and b = c= 0 kcal/mol.

5.2.35. ZnCl2 (l -tc), BaCl2 (*).

Cells: Zn|ZnCl2 , BaCl2 |Cl2 |C. [59]'

Lantratov and Alabyshev [59] have studied this

system under equilibrium conditions. Systematic

errors are present in their measurement. It is re- ported [59] that the excess free energy of the mixture

is negative, and less negative than for the mixture

ZnCl2 , NaCl (sec. 5.2.31).

5.2.36. AgBr(l —x), LiBrfi*;)

Cells: Ag|AgBr, LiBr|Br2 |C. [63]

Tables: 7, 43

Figure: 8a

Parameters for the excess free energy (550 °C): a = 1.8 kcal/mol

6 = 0.0 kcal/mol

c = 0.0 kcal/mol

Estimated uncertainty in 4GE (*=0.5): 0.15 kcal/mol

Parameters for the excess entropy (550 °C):

a' = — 0.45 e.u.

6' = 0.45 e.u. c = 0.00 e.u.

Estimated uncertainty in 4S

E

(* = 0.5): 0.15 e.u.

Salstrom and Hildebrand [63] used an equilibrium

cell for this system. Air and hydrolysis products were removed with a stream of dry hydrogen bromide in the pretreatment of the salts in the molten

state. As already noted (sec. 5.1.10) the results of

this study are of high quality.

One composition, * = 0.89, was not included for

the excess entropy calculations since the investigation of this composition was restricted to a relatively

small temperature range.

5.2.37. AgBr(l —*), NaBr(*).

Cells: Ag|AgBr, NaBr|Br2 |C. [67]

Tables: 7, 44

Figure: 8b

Parameters for the excess free energy (600 °C):

a= 1.05 kcal/mol

6 = 0.00 kcal/mol

c = 0.00 kcal/mol

20
a>o

^\£

o

Figure 8. Experimental values of p-^KBJx2 and s

a. AgBr, LiBr

0 Salstrom and Hildebrand [63] , 550 °C

b. AgBr, NaBr

0 Salstrom [67], 600 °C

c. AgBr, KBr

© Salstrom [68] , 600 °C

d. AgBr, RbBr

© Salstrom [65] . 550 °C

e. AgBr, PbBr2 © Salstrom [65], 550 °C

AgBr/x2 molten binary bromide mixtures. The limits of uncertainty and the solid lines are the result of the present analysis.

Estimated uncertainty in 4G£ (x — 0.5): 0.1 kcal/mol

Salstrom [67] used the same experimental procedure for these cells as for the cells Ag|AgBr,

LiBr|Br2 |C (sec. 5.2.36). As noted in section 5.1.10,

this formation cell has been studied under equilibrium conditions.

Inspection of table 44 shows that the reported

data only allow an estimate for the excess entropy.

The values thus approximated are: a' = 1.8 e.u.,

b' = c' — 0.0 e.u., with an uncertainty in 4S£(x — 0.5)

of 0.5 e.u.

21
5.2.38. AgBr(l-jt),KBr(r).

Cells: Ag|AgBr, KBr|Br2 |C. [68]

Tables: 7, 45

Figure: 8c

Parameters for the excess free energy (600 °C): a = — 1.45 kcal/mol

b = — 0.30 kcal/mol

c= 0.00 kcal/mol

Estimated uncertainty in 4G£

(* = 0.5): 0.10 kcal/mol

The above mentioned cell has been investigated

by Salstrom [68]. The experimental procedures,

essentially, were the same as in the studies of the

related systems: Ag|AgBr, LiBr|Br2 |C [63] (sec.

5.2.36) and Ag|AgBr, NaBr|Br2 |C [67] (sec. 5.2.37).

Inspection of table 45 shows that the excess

entropy of this mixture is nearly zero.

5.2.39. AgBr(l —*), RbBr(*).

Cells: Ag|AgBr, RbBr|Br2 |C. [65]

Tables: 7, 46

Figure: 8d

Parameters for the excess free energy (550 °C): a = —2.6 kcal/mol

b = 0.0 kcal/mol

c = 0.0 kcal/mol

Estimated uncertainty in ^GE{x= 0.5): 0.2 kcal/mol

The cell was studied by Salstrom [65], using

equilibrium techniques. Inspection of figure 8d

suggests an asymmetrical free energy of mixing but

the range of compositions studied was insufficient

to determine the asymmetry quantitatively.

The excess entropy data suggest a small negative excess entropy for this mixture (a' = — 0.5 e.u.,

6' = c' = 0.0 e.u.); the data are rather scattered and

the result is at best qualitative.

5.2.40. AgBr(l -x), PbBr2 (*).

Cells: Ag| AgBr, PbBr2 |Br2 |C. [61]

Tables: 7, 47

Figure: 8e

Parameters for the excess free energy (550 °C) a = 0.05 kcal/mol

6 = 0.15 kcal/mol

c = 0.00 kcal/mol

Estimated uncertainty in 4>GE(x = 0.5): 0.05 kcal/mol

Parameters for the excess entropy (500 °C): a = b' = c — 0 e.u.

Estimated uncertainty in 4S£(;c = 0.5): 0.5 e.u.

The equilibrium properties of this cell have been

discussed in section 5.1.10. The Salstrom emf data

[61] show near ideality for this mixture. Although

the entropy data (table 47 and figure 8e) are scat- tered, it is evident that the excess entropy of this

system is about zero.

5.2.41. CdBr2 (l -jc), KBr(*).

Cells: Cd|CdBr2 , KBr|Br2 |C. [69]

Table: 48

Figure: 9

Parameters for the excess free energy (597.5 °C): a = — 8.3 kcal/mol

b = — 6.6 kcal/mol

c = 0.0 kcal/mol

Estimated uncertainty in 4>GE{x = 0.5): 1.0 kcal/mol

The cell Cd|CdBr2 |Br2 |C was investigated by

Lantratov and Shevlyakova [69] and has been discussed in section 5.1.11. As noted, further studies

of the cell appear desirable. The parameters for

the excess free energy are estimates only.

5.2.42. PbBr2 (l — *), NaBrfir).

Cells: Pb|PbBr2 , NaBr|Br2 |C. [73]

W|PbjPbBr2 , NaBr|glass|PbBr2 (x = 0.6).

NaBr(.r= 0.4)|Br2 |C. [33,34]

Table: 9, 49

Figure: 10a

FIGURE 9. Experimental values of P-caBrJ*

2 the molten binary

mixture CdBr2 , KBr(x). The solid line is the result ofthe present

analysis.

© Lantratov and Shevlyakova [69], 597.5 °C

22
Figure 10. Experimental values of p,fbBl. 2 /x2 and SpbBr2 /x2 in molten binary bromide mixtures. The limits of uncertainty and the solid

lines are the result of the present analysis.

a. PbBr2 , NaBr

© Lantratov and Shevlyakova [73], 589 °C

b. PbBr2 , KBr

© Lantratov and Shevlyakova [71], 550 °C

c. PbBr2 , ZnBr2 © Salstrom [70], 500 °C

Parameters for the excess free energy (589 °C): a = — 1.31 kcal/mol

b = — 0.16 kcal/mol

c = 0.00 kcal/mol

Estimated uncertainty in GE(x = 0.5): 0.2 kcal/mol

The cell Pb|PbBr2 |Br2 |C was discussed in section 5.1.12. Inspection of table 9 shows that there

is an appreciable difference between the E° values

of Lantratov and Shevlyakova [73] and from the

other investigations.

Dijkhuis and Ketelaar [33, 34] determined the excess free energy of this mixture with a cell in

which glass functions as a cation selective membrane. Taking due cognizance of the uncertainties

in the E° value of the formation cell [73], the results

of these two investigations are in surprisingly good

accord.

5.2.43. PbBr2 (l -jc), KBr(x).

Cells: Pb|PbBr2 , KBr|Br2 |C. [71]

Tables: 9, 50

Figure: 10b

Parameters for the excess free energy (550 °C): a = — 27.5 kcal/mol

6= 32.5 kcal/mol

c = — 50.0 kcal/mol

Estimated uncertainty in 4G£

(^ = 0.5): 0.7 kcal/mol

The experimental uncertainties involved in the

23
cell of Lantratov and Shevlyakova [71] have been

discussed in sections 5.1.12 and 5.2.42.

5.2.44. PbBr2 (l -x), ZnBr2 (x).

Cells: Pb|PbBr2 (l — *), ZnBr2 (*)|Br2 |C. [70]

Tables: 9, 51

Figure: 10c

Parameters for the excess free energy (500 °C): a = 0.05 kcal/mol

6 = 0.40 kcal/mol

c = 0.00 kcal/mol

Estimated uncertainty in 4G£

(* = 0.5): 0.2 kcal/mol

As seen in table 9, the E° values of Salstrom [70]

for cells such as Pb|PbBr2 |Br2 |C are in good agreement with the results from thermochemical data.

This is support for the recommendation of the excess free energy as an accurate result.

The temperature dependence of the Salstrom

E° values does not agree with the thermochemical

data, so that the excess entropies may be too high.

5.2.45. Agl(l -x), KI(x).

Cells: Ag|AgI, KI|I2 |C. [75]

Tables: 10, 52

Figure: 11

Parameters for the excess free energy (600 °C): a =—1.95 kcal/mol

6= 1.20 kcal/mol

c = 0.1 |kcal/mol

Estimated uncertainty in 4GE

(* = 0.5): 0.2 kcal/mol

Parameters for the excess entropy (600 °C):

a' = 0.0 e.u.

6' = 3.7 e.u. c = 0.0 e.u.

Estimated uncertainty in 4S

E

(* = 0.5): 0.2 e.u.

Sternberg, Adorian, and Galasiu [74, 75, 76]

devised a reversible iodine electrode (sec. 5.1.13).

The E° value agrees well with the thermochemical

value, so that the excess properties may be accepted

as quite reliable.

The excess entropies were calculated from the

equations for the temperature dependence of the

emf data as published by these investigators [75].

5.2.46. Cdl2 (l -ar), Nal(*).

Cells: W|Cd|CdI2 , Nal | glass |CdI2 (* = 0.5),

NaI(* = 0.5)|Cd|W. [33,34]

Parameters for the excess free energy (600 °C): a = — 2.28 kcal/mol

6 = — 1.89 kcal/mol

c= 0.00 kcal/mol

Figure 11. Experimental values of ,/x2 in the molten binary

mixture Agl. KI(x). The solid line and the limits of uncer- tainty are the result of the present analysis.

© Sternberg. Adorian. Galasiu [75], 600 °C

Estimated uncertainty in 4GE

(* = 0.5): 0.5 kcal/mol

Dijkhuis and Ketelaar [33, 34] have studied this

mixture with cells having glass as cation-selective

membranes (sec. 5.1.15). The technique is discussed

in section 5.1.15.

5.2.47. Pbl 2 (l —*), Nalpr).

Cells: W|Pb|PbI2 , Nal | glass | PbT(* = 0.6),

NaI(*=0.4)|Pb|W. [33.34]

Parameters for the excess free energy (600 °C): a = — 0.46 kcal/mol

6 = — 0.14 kcal/mol

c = 0.00 kcal/mol

Estimated uncertainty in 4GE (*=0.5): 0.2 kcal/mol

Dijkhuis and Ketelaar [33, 34] have studied this

mixture with cells having glass as a cation-selective

membrane (sec. 5.1.15).

5.2.48. AgBr(l —*), AgCl(*).

Cells: Ag| AgBr, AgCl|Br2 |C. [64]

Tables: 7, 53

Figure: 12

24
FIGURE 12. Experimental values of 4

t bAgB/x2 and s

KBr /x2 in the molten binary mixture AgBr, AgCl(x). The solid lines are

the result of the present analysis.

O Murgulescu. Marchidan [64], 600 °C

Parameters for the excess free energy (600 °C): a = 3.25 kcal/mol

b = — 4.43 kcal/mol

c= 5.22 kcal/mol

Estimated uncertainty in 4GE (x=0.5): 0.1 kcal/mol

Parameters for the excess entropy (600 °C):

a' = 2.63 e.u.

b' = — 15.06 e.u.

c' — 13.07 e.u.

Estimated uncertainty in 4S£

(* = 0.5): 0.2 e.u.

Murgulescu and Marchidan [64] used equilibrium techniques (sec. 5.1.10) and the E° value

is in excellent agreement with thermochemical data

(sec. 5.1.10); the random error is low. It therefore

appears that the curvatures in the versus * graph and the corresponding excess entropy plot are physically significant.

5.2.49. Agl(l-*), AgCl(*).

Cells: Ag|AgI, AgCl|I2 |C. [76]

Table: 54

Figure: 13a

Parameters for the excess free energy (600 °C): a = 0.45 kcal/mol

6 = 0.00 kcal/mol

c = 0.00 kcal/mol

Estimated uncertainty in 4GE

(* = 0.5): 0.15 kcal/mol

Parameters for the excess entropy (600 °C):

a' = — 0.57 e.u. 6'= 3.07 e.u.

c' = 0.00 e.u.

Estimated uncertainty in 4vSt’ (* = 0.5): 0.2 e.u.

CD

Figure 13. Experimental values of ufjyi1 and s’L./x2 in molten binary mixtures. The solid lines are the result of the present analysis.

a. Agl, AgCl

O Sternberg, Adorian, Galasiu [76], 600 °C

b. Agl, AgBr

O Sternberg, Adorian, Galasiu [76], 600 °C

Sternberg, Adorian and Galasiu [76] studied this

mixture using the conventional silver electrode and

a reversible iodine electrode of their design (sec.

5.1.13). The correspondence between the experimental E° value and the thermochemical values

is good.

5.2.50 Agl(l -jt), AgBr(*).

Cells: Ag|AgI, AgBr|I2 |C. [76]

Table: 55

Figure 13b

Parameters for the excess free energy (600 °C):

a= 1.10 kcal/mol

b — 0.00 kcal/mol

c=0.00 kcal/mol

25
Estimated uncertainty in 4GE (*=0.5): 0.2 kcal/mol

Parameters for the excess entropy (600 °C): a' = — 0.30 e.u. b'= 1.45 e.u. c — 0.00 e.u.

Estimated uncertainty in 4SE

(* = 0.5): 0.2 e.u.

Sternberg, Adorian and Galasiu [76] investigated this mixture using the same technique as

for the Agl, KI (sec. 5.2.45) and Agl, AgCl (sec.

5.2.49) mixtures. As already noted (sec. 5.1.13)

these results are clearly of high quality.

5.2.51. KBr(l —*), KC1(*).

Cells: C|Br2 |KBr|glass|KBr(l — *), KCl(*)|Br2 |C.

Table: 56 [9] Figure: 14

Parameters for the excess free energy (800 °C): a = 0.50 kcal/mol

6 = — 0.55 kcal/mol

c= 0.00 kcal/mol

Estimated uncertainty in 4GE (*=0.5): 0.1 kcal/mol

Parameters for the excess entropy (800 °C):

a' — — 0.89 e.u. b'= 1.20 e.u. c = — 2.33 e.u.

Estimated uncertainty in 4SE (*=0.5): 0.2 e.u.

Ostvold [9] used a glass cation selective membrane for the determination of the excess properties of mixtures KBr, KC1. While the results

FIGURE 14. Experimental values of /i.^ Br /x2 and s^

Br /x2 in the molten binary mixture KBr(l — x), KCl(x).

O Ostvold [9], 800 °C

indicate that there is some curvature in the r^^/*2 versus * plot, the scatter in the data is such that the

assumption of the straight line relationship seems

justified.

5.2.52. NaBr(l —*), NaCl(*).

Cells: C|Br2 |NaBr| glass |NaBr(l — *),

NaCl(*)|Br2 |C. [9, 84]

Table: 57

Figure: 15

Parameters for the excess free energy (800 °C): a = 0.40 kcal/mol

6 = — 0.10 kcal/mol

c= 0.00 kcal/mol

Estimated uncertainty in 4G£

(* = 0.5) 0.1 kcal/mol

Parameters for the excess entropy (800 °C):

a' = — 0.39 e.u. 6'= 0.33 e.u. c = — 0.67 e.u.

Estimated uncertainty in 4S£

(* = 0.5) 0.1 e.u.

Ostvold [9] and Sternberg and Herdlicka [84]

both used glass cation-selective membranes for

the investigations of this system. It is seen from fig- ure 15 that the two investigations are in excellent

accord. The Ostvold [9] data show a somewhat

smaller scatter and were used for the determination

of the parameters for the excess free energy.

v

Figure 15. Experimental values of /XnW*2 and s§aBJx2 in the binary mixture NaBr(l — x), NaCl(x).

Q Ostvold [9]. 800 °C

A Sternberg. Herdlicka [84] 800 °C

26
5.2.53. PbBr2 (l -*), PbCl2 (*).

Cells: Pb|PbBr2 (l —x), PbCl2 (x) |Br2 |C. [72]

Tables: 9, 58

Figure: 16

Parameters for the excess free energy (500 °C): a = — 2.6 kcal/mol

6= 0.0 kcal/mol

c— 0.0 kcal/mol

Estimated uncertainty in 4>GE (x = 0.5) : 0.5 kcal/mol

As noted elsewhere (table 9) the E° values of

Salstrom and Hildebrand [72] are in accord with

those of Hamer, Malmberg and Rubin [12] calculated from thermochemical data. The temperaturedependence observed by Salstrom and Hildebrand seems to be questionable. The /xE

bBrJx

2 values are quite scattered and the excess free energy of this

mixture seems to be appreciably negative.

Figure 16. Experimental values of p.pbBr.Jx

2 and SpbBr2 /x2 in the molten binary mixture PbBr2 (l — x), PbCl2 (x). © Salstrom, Hildebrand [72], 500 °C

6. Cumulative Table of Excess Free Energies

According to the previous analysis the parameters

a, b, and c in the equation for the excess free energy

of mixing,

GE = x(l— x) (

a

+ bx+cx2 ),

have the following values:

Mixture Temperature Reference

GE = x (||— x) (a + bx+cx2

)

a b c

AgCl, LiCl(x)

AgCl, NaCl(jc)

rc>

[20, 26]

[19,25,27]

kcal/mol 2.1 0.8kcal/mol 0

0

kcal/mol 0

0

AgCl, KCl(x) 650 [22, 24] -1.5 0.4 0

AgCl, PbCl2 (*) 550 [23] -0.15 .2 0

CdCl2 , NaCl(x) 600 [33, 34, 36] -4.45 -3.85 0

CdCl2 , KCl(x) 600 [36] -7.5 -10.7 0

CdCl2 , BaCl2 (x) 600 [36] -1.0 -8.8 0

CeCh, NaCl(jc) 800 [37] -2.7 -13.6 9.3 CeCfi, KCl(x) 850 [37, 38] -1.87 -31.75 20.48

CeCb, CaCl2 (jc) 850 [39] 4.80 -8.79 5.37

MgCL>, LiCl(x)

MgCl,, NaCl(x)

700 [40]

[9, 38, 40, 41]

3.95

-4.80

-5.75

-9.39

0

7.08

MgCL, KC\(x) 800 [38, 40, 41] -12.84 -11.88 12.96

CaCl2 , NaCl(*) 850 [9] -2.45 -0.45 0

SrCL», NaCl(jc) 850 [9] -0.02 -1.92 1.03

BaCl>, NaCl(x) 850 [9] .08 -0.04 0

PbCl2 , LiCl(x) 600 [45, 46] .45 -.55 0

PbCl2 , NaCl(x) 600 [33. 34. 44.]

[45, 46. 48]

-1.52 -.39 0

PbCl2 , KCl(x) 600 [44. 45, 46. 49] -5.0 .0 0

335-493 0-69—3 27
Mixture

TemperReference

GE = x (1— x) {a+ bx+ cx2

) ature a b c

(°C) kcal/mol kcal/mol kcal/mol PbCl2 , RbCl(x) 600 [46] -6.5 0 0

PbCl2 , CsClU) 650 [44] -7.3 -5.2 0

Pbci,, CaCi2 u) 650 [45] 0.6 -2.8 0

PbCb, SrCl2 (jc) 650 [45] 1.3 -1.6 0

PbCl>, BaCl2 (:r) 650 [45] -0.7 -3.0 0

PbCl>, ZnCl2 (:r) 500 [50, 51] - 1.65 1.15 0

ZnCb, LiCl(jc) 550 [58] 2.9 -1.3 0

ZnCl2 , NaClU) 600 [59, 85] -4.37 -5.54 0

ZnCl2 , KCl(x) 550 [59, 60] -10 -18 0

ZnCb, BaCl2 [59]

[63]

0 3= a 2= —

AgBr, LiBr(x) 550 1.8 0 0

AgBr,NaBr(x) 600 [67] 1.05 0 0

AgBr,KBr(x) 600 [68] -1.45 -0.30 0

AgBr, RbBr(x) 550 [65] -2.6 0 0

AgBr, PbBr2 (x) 550 [66] 0.05 .15 0

CdBr2 , KBr(x) 597.5 [69] -8.3 -6.6 0

PbBr2 , NaBr(x) 589 [73] -1.31 -0.16 0

PbBr>, KBr(jc) 550 [71] -27.5 32.5 -50.0

PbBr>, ZnBr>(jc) 500 [70] 0.05 0.40 0

Agl. KI(*) 600 [75] -1.95 1.20 .1 Cdl,, Nal 600 [33, 34]

[33, 34]

-2.28 -1.89 0

Pbl2 , Nal 600 -0.46 -0.14 0

AgBr, AgCl(x) 600 [64] 3.25 -4.43 5.22

Agl, AgCl(x) 600 [76] 0.45 0 0

Agl, AgBr(jc) 600 [76] 1.15 0 0

KBr, KCl(x) 800 [9] 0.50 -.55 0

NaBr, NaCl(jc) 800 [9, 84] .40 -.10 0

PbBr,, PbCl2 (x) 500 [72] -2.6 0 0

7. Tables of E° Values and Excess Properties for Individual Mixtures

Table la. E°(mV) = a+ bt + ct2 for the cell Ag| AgCl | CI2 1

C

The parameters a, b, and c have been generated from literature values by a linear and

a quadratic least-squares analysis.

a b X 103 cX 106 Standard

deviation (mV)

Temperature

range (°C)

Reference

1026.5 -263.0 0 max. 2.0 530-920 [16]

1093.0 -484.9 173.2 0.5 455-900 [21]

1066.6 -372.8 72.4 .9 482-800 [19, 20]

1028.6 -275.4 0 .1 480-638 [22, 27]

1064.2 -330.7 0 1.5 476-628 [24, 25]

1042.6 -285.8 0 0.4 498-600 [23]

*1087.7 *-485.3 *204.7 .3 500-600 [11]

*Thermochemical data.

28
TABLE lb. E° (mV) of the cell Ag|AgCl|Cl2 |C at various temperatures (°C) according to table la

(Extrapolated values are included.)

500° 550° 600° 700° 800° 900° Standard

deviation (mV)

Temperature

range (°C)

Reference

895.0 881.5 868.4 842.1 815.8 789.5 max. 2.0 530-920 [16]

893.9 878.7 864.5 838.5 816.0 796.9 0.5 455-900 [21]

898.3 883.4 869.0 841.1 814.7 789.8 .9 482-800 [19,20]

890.9 877.2 863.4 835.9 808.3 780.7 .1 480-638 [22, 27]

898.8 882.3 865.8 832.7 799.7 766.6 1.5 476-628 [24, 25]

899.7 885.4 871.1 842.5 814.0 785.4 0.4 498-600 [23]

*896.0 *883.0 *870.0 *848.0 *826.0 *805.0 .3 500-600 [11]

*Thermochemical data.

Table 2a. E°(/nE) =a + bt + ct2 /ort^ece//Be|BeCl2 |Cl2 |C

The parameters a, b and c have been generated from literature values by a linear

and a quadratic least-squares analysis.

a b X 103 cX 106 Standard

deviation (mV)

Temperature

range (°C)

Reference

2264.0 -850.0 0 0 400-500 [28]

2170.5 -652.6 0 .6 410-550 [29]

*2369.3 *-450.0 *0 .4 450-550 [11]

*2324.8 *-804.7 *206.4 .1 326-626 [13]

*Thermochemical data. TABLE 2b. E° (mV) of the cell Be|BeCl2 |Cl2 |C at various temperatures (°C) according

to table 2a

(An extrapolated value is included).

450° 500° 550° Standard

deviation (mV)

Temperature

range (°C)

Reference

1881 1839 1796 0 400-500 [28]

1877 1844 1812 .6 410-550 [29]

*2167 *2144 *2122 .4 450-550 [11]

*2004.5 *1974.1 *1944.6 .1 326-626 [13]

*Thermochemica] data.

29
Table 3a. E° (mV) = a + bt + ct2 for the cell CdlCdCblCklC

The parameters a, b, and c have been generated from literature values by a linear

and a quadratic least-squares analysis.

a fix 103 cX 106 Standard

deviation (mV)

Temperature

range (°C)

Reference

1556.6 -148.8 -353.4 1.5 600-771 [35]

1669.6 -553.3 0 1.2 578-687 [36]

Table 3b. E° (mV) of the cell Cd|CdCl2 |Cl2 |C at various temperatures (°C) according to table 3a

(Extrapolated values are included)

600° 650° 700° 750° Standard

deviation (mV)

Temperature

range (°C)

Reference

1340.1 1310.6 1279.2 1246.2 1.5 600-771 [35]

1338

*1331

1310 1282 1255 1.2 578-687 [36]

*Thermochemical data

Table 4a. E° (mV) = a+bt + ct

2 for the cell Mg|MgCl2 |Cl2 |C

Tha parameters a, b, and c have been generated from literature values by a linear and

a quadratic least-squares analysis.

a b X 103 cX 106 Standard

deviation (mV)

Temperature

range (°C)

Reference

4673.5 -5165.2 2980.0 2.8 704-799 [35]

3750.2 -2650.0 1325.2 1.5 718-770 [40]

2955.7 -658.7 44.9 0.0 726-1026 [13]

Table 4b. E° (mV) of the cell Mg|MgCl2 |Cl2 |C at various temperatures (°C) according to table 4a

(Extrapolated values are included.)

750° 800° 850° 900° Standard

deviation (mV)

Temperature

range (°C)

Reference

2475.8 2448.5 2436.1 2438.6 2.8 704-799 [35]

2508 2478 2455 2439 1.5 718-770 [40]

*2487.0 *2457.0 *2428.2 *2399.0 0.0 726-1026 [13]

*2460 [11]

*Thermochemical data.

30
Table 5a. E° (mV) = a + bt + ct

2 for the cell Pb

| Pb C1-2 1 Cl-^ |

C

The parameters a, b, and c have been generated from literature values by a linear

and a quadratic least-squares analysis.

a b x 103 cX 106 Standard

deviation (mV)

Temperature

range (°C)

Reference

1578.2 -602.0 0 not reported 500-620 [44]

1524.8 -411.3 -177.8 1.7 553-809 [35]

1538.3 -527.7 0 1.0 532-681 [45]

1538.3 -527.7 0 1.0 550-600 [46, 47]

1635.7 -730.5 0 0.8 501-607 [49]

1581.5 -617.6 0 .7 499-582 [50]

1563.0 -533.5 0 not reported not reported [51]

1537.0 -533.5 0 1.0 527-634 [38]

*1551.0 *- 560.0 *0 0 500-600 [11]

*1590.3 *-681.3 *102.0 .1 526-826 [13]

*Thermochemical data.

Table 5b. E° (mV) of the cell Pb|PbCl2 |Cl2 |C at various temperatures (°C) according to table 5a

(Extrapolated values are included)

550° 600° 650° 700° Standard

deviation (mV)

Temperature

range (°C)

Reference

1247 1217 1187 1157 not reported 500-600 [44]

1244.8 1214.0 1182.4 1149.8 1.7 553-809 [35]

1248 1222 1195 1169 1.0 532-681 [45]

1248 1218 1195 1169 1.0 550-600 [46, 47]

1234 1197 1161 1124 0.8 501-607 [49]

1242 1211 1180 1149 .7 499-582 [50]

1242 1213 1183 1154 not reported not reported [51]

1243.6 1216.9 1190.2 1163.6 1.0 527-634 [38]

*1243 *1215 0 500-600 nn

*1246.5 *1218.2 *1190.6 *1163.4 .1 526-826 [13]

*Thermochemical data

31
Table 6a. E° (mV) = a + bt + ct 2 for the cell Zn|ZnCl2 |Cl2 |C

The parameters a, b, and c have been generated from literature values by a linear

and a quadratic least-squares analysis.

a b X 103 cX 106 Standard

deviation (mV)

Temperature

range (°C)

Reference

1866 -530 0 not reported not reported [56]

1568.8 565.0 -1137.1 4.1 418-699 [35]

1909.9 -673.3 0 0.2 440-530 [57]

1919.1 -693.7 0 .5 501-575 [50]

1919 -711 0 not reported 550-600 [58]

1904.6 -681.9 0 2.0 441-570 [59]

*1860.3 *-514.3 *0 0.3 300-600 [11]

*Thermochemical data

TABLE 6b. E° (mV) of the cell Zn|ZnCl2 |Cl2 |C at various temperatures (°C) according to table 6a

(Extrapolated values are included)

450° 500° 550° 600° Standard

deviation (mV)

Temperature

range (°C)

Reference

1627 1601 1574 1548 not reported not reported [56]

1592.8 1567.0 1535.6 1498.4 4.1 418-699 [35]

1606.9 1573.2 1539.6 1505.9 0.2 440-530 [57]

1606.9 1572.3 1537.6 1502.9 .5 501-575 [50]

1599 1563 1529 1493 not reported 550-600 [58]

1598 1564 1530 1495 2.0 441-570 [59]

1588.5 1553.0 not reported not reported [61]

*1629 *1603 *1577 *1552 0.3 300-600 [11]

*Thermochemical data

Table 7a. E° (mV)= a+ bt + ct2 for the cell Ag| AgBr|Br2 |C

The parameters a, b, and c have been generated from literature values according to a linear and a quadratic least-squares analysis.

a b X 103 cX 10K Standard

deviation (mV)

Temperature

range (°C)

Reference

930.0 -287.3 0 0.25 442-565 [63]

928.9 -289.1 0 .3 510-600 [64]

32
TABLE 7b. E° (mV) of the cell Ag| AgBr|Br2 |C at various temperatures (°C) according to table 7a

(Extrapolated values are included)

450° 500° 550° 600° Standard

deviation (mV)

Temperature

range (°C)

Reference

800.7 786.4 772.0 757.6 0.25 442-565 [63]

798.8 784.4 769.9 755.5 .3 510-600 [64]

*795 *781 *767 *754 [12]

*Thermochemical data

Table 8a. E° (mV) = a + bt + ct2 /or the cell Cd|CdBr2 |Br2 |C

The parameters a, b, and c have been generated from literature values according to a linear and a quadratic least-squares analysis.

a b X 103 c X 10B Standard Temperature Reference

deviation (mV) range (°C)

1425.3 -498.9 0 [69]

TABLE 8b. E° (mV) of the cell Cd|CdBr2 |Br2 |C at various temperatures

(°C) according to table 8a

600° 650° Standard

deviation (mV)

Temperature

range (°C)

Reference

1126.0 1101 [69]

*1085 [12]

*Thermochemical data

Table 9a. E° (mV) = a + bt + ct

2 /or the cell Pb|PbBr2 |Br2 |C

The parameters a, b, and c have been generated from literature values according to a linear and a quadratic least-squares analysis.

a b x 103 c x 106 Standard

deviation (mV)

Temperature

range (°C)

Reference

883.9 1815.5 -2984.9 8.9 321-568 [71]

1216.5 -89.2 -561.7 2.4 423-532 [70]

1335.1 -606.6 0 0.4 438-576 [72]

1429.0 -1000.1 409.0 0 500-600 [12]

*1340.7 *-679.5 *150.1 .06 426-726 [13]

*Thermochemieal data. 33
Table 9b. E° (mV) of the cell Pb|PbBr2 |Br2 |Cat various temperatures (°C) according to table 9a

(Extrapolated values are included)

400° 450° 500° 550° 600° Standard

deviation (mV)

Temperature

range (°C)

Reference

1133 1096 1045 979.5 898.6 8.9 321-568 [71]

1091 1063 1031 997.5 960.8 2.4 423-532 [70]

1092.5 1062 1032 1001 971.1 0.4 438-576 [72]

*1094 *1062 *1031 *1003 *976 0 500-600 [12]

*1093 *1065.3 *1038 *1012.4 *987.1 .06 426-726 [13]

*Thermochemieal data

Table 10a. E° (mV) / a + bt + ct 2 for the cell Ag| Agl |I2 1

C

The parameters a, b, and c have been generated from literature values according to a linear and a quadratic

least-squares analysis.

a b X 103 cX 106 Standard

deviation (mV)

Temperature

range (°C)

Reference

700 -250 0 1.5 [74]

Table 10b. E° (mV) of the cell Ag| Agl |/2 1 C at various temperatures (°C) according to table 10a

600° 650° 700° Standard

deviation (mV)

Temperature

range (V!) Reference

550 537.5 525 1.5 [74]

*563 [12]

*Thermochemical data

34
Table 11. E° (mV)= a+ bt + ct2 for the cells Alkali Metal\Alkali Halide\Halide\C

The parameters a , b , and c have been generated from thermochemical literature values [13] by a linear and a quadratic least-squares analysis.

a b X 103 cX 106 Standard

deviation (mV)

Temperature

range (°C)

Li | LiF | F2 1 C 5890.1 -830.4 64.0 0.05 926-1226

Li j LiCl | Cl2 1 C 3830.9 -573.3 0 7.4 626-926

LiiLiBr|Br2 |C 3469.0 -668.8 91.1 0.1 626-926

Li j Lil 1

1

2 1 C 2829.0 -626.2 88.5 .03 526-826

Na|NaF F2 |C 6206.5 -1809.2 113.8 0.03 1026-1326

Na|NaCl|Cl2 |C 2830.4 1746.1 -1536.2 14.7 826-1126

Na NaBr|Br2 |C 2497.6 1803.8 - 1559.7 14.7 826-1126

Na|NaI|I2 |C 1553.3 2725.8 -2061.8 10.3 726-1026

K|KF|F2 |C 6015.5 -1707.9 106.0 0.07 926-1226

K|KC1|C12 |C 4708.6 -1680.8 141.6 .1 826-1126

K|KBr|Br2 C 5085.7 -3106.5 922.4 7.1 826-1126

K KI|I2 |C 3188.6 68.6 -744.0 7.7 726-1026

Table 12. Excess properties of mixtures

AgCl(l — x), LiCl(x)

(The numbers following the ± in column 2 are precision

estimates.)

X Higci/*

2 (kcal/mol) s E

ASC Jx

2 (e.u.)

Reference [20], 800 °C

0.0950 9.455 ±8.687 8.432

.1850 -0.473 ±0.606 - 80.663

.4150 1.861 ±0.577 -3.107

.7480 2.043 ±0.067 -0.012

.7620 2.009 ±0.037 -.409

.8090 2.108 ±0.055 .504

.8950 2.221 ±0.051 -1.791

.9714 2. 122 ±0.032 0.833

X A'-Agci/*

2 (kcal/mol) ( e - u-)

Reference [26], 600 °C

0.1960 3.482 ±0.420 1.380

.3100 2.161 ±0.120 -0.408

.4270 2.062 ±0.062 1.177

.5310 1.972 ±0.048 1.268

.7480 2.015 ±0.025 -0.161

.8640 2.205 ±0.018 -.516

35
Table 13. Excess properties of mixtures

AgCl(l — x), NaCl(x)

(The numbers following the ± in column 2 are precision

estimates.)

Table 14. Excess properties of mixtures

AgCl(l — x), KCl(x)

(The numbers following the ± in column 2 are precision

estimates.)

X P-Agci/*

2 (kcal/mol) ^Agci/*

2

( e- u-)

Reference [19], 800 °C

0.1500 3.791 ±1.229 -6.356

.2450 1.077 ±0.962 -1.460

.3330 0.749 ±0.228 -1.310

.3540 .221 ±0.277 -0.184

.3650 1.038 ±0.157 -.848

.3850 0.249 ±0.187 .545

.4190 .579 ±0.145 .854

.4500 .434 ±0.182 .718

.4950 .895 ±0.131 .621 .6490 .844 ±0.104 1.796

.7910 .999 ±0.044 0.184

.9022 .959 ±0.025 .246

.9687 .989 ±0.025 .093

X p. Agci/*

2 (kcal/mol) s E

AeJx2 (e.u.)

Reference [27], 800 ° c

0.100 4.312 ±4.658 -136.750

.250 1.564 ±0.572 -5.718

.400 0.886 ±0.155 0.245

.550 1.112±0.037 -.839

.700 0.922 ±0.012 .706

X p

E

AsC Jx

2 (kcal mol) S AgCl/*

2

( e - U‘)

Reference [25], Stern, 800 °C

0.4740 0.083 ±0.196 9.011

.6669 .669 ±0.099 3.179

.7470 .613 ±0.078 3.182

.8767 .438 ±0.044 3.327

.9109 .055 ±0.042 11.629

.9225 -.279 ±0.042 4.365

X P-Agci/*

2 (kcal/mol) se

AsJx2 (e.u.)

Reference [24], 700 °C

0.4091 — 1 . 1 16 ± 0.221 7.108

.5734 -1.086 ±0.148 2.770

.8093 -0.473 ±0.053 3.102

.9018 -.766 ±0.042 4.001

.9201 -.807 ±0.058 3.260

.9353 -1.605 ±0.051 0.801

X P-Agci/*

2 (kcal/mol) 5

abci/*2

( e- u-)

Reference [22], 650 °C

0.100 -1.845 ±0.922 4.84

.200 — 0.173±0.115 121.925

.300 -1.741 ±0.051 -0.794

.400 -1.543 ±0.071 -4.828

.500 -1.430 ±0.009 138.132

.600 -1.485 ±0.014 782.303

.650 — 1.453±0.012 -1.223

Table 15. Excess properties of mixtures

AgCl(l — x), PbCl2 (x) (The numbers following the± in column 2 are precision

estimates.)

X ^Agci/*

2 (kcal/mol) s £gCA

2

( e- u-)

Reference [23], 550 °C

0.200 0.058 ±0.288 -3.345

.400 — ,173±0.071 -1.168

.550 -.122 ±0.039 -0.084

.700 -.095 ±0.028 -.452

.800 -.053 ±0.018 -.483

.900 .039 ±0.021 -.253

36
Table 19. Excess properties of mixtures

CeC1.3(l — x). NaCl(x)

Table 16. Excess properties of mixtures

CdCl2 (l — x), NaCl(x)

(The numbers following the ± in column 2 are precision

estimates.)

X A'-cdci A

2 (kcal/mol) SCdCh^X ( e - u-l

Reference [36], 600 °C

0.200 5.765 ±2.421 -46.005

.300 0.821 ±1.128 -6.790

.400 -.835 ±0.431 - 9.484

.500 -2.693 ±0.351 -7.628

.600 -3.300 ±0.270 -7.149

.700 -3.531 ±0.168 1.158

Table 17. Excess properties of mixtures

CdCL>(l — x), KCl(x)

(The numbers following the ± in column 2 are precision

estimates.)

X A'-cdCh/*

2 (kcal/mol) ^CdCte^ (c.U.)

Reference [36], 600 °C

0.100 7. 149 ±13.375 68.950

.300 - 4.561 ± 1.229 -11.710

.400 - 5.880 ± 0.662 -12.712

.500 - 7.306 ± 0.461 -3.846

.600 - 10.370 ± 0.295 -10.621

.700 — 11.897 ± 0.180 -7.313

Table 18. Excess properties of mixtures

CdCl-2 ( 1 — x), BaCl2 (x)

X MrdciA

2 (kcal/mol) 5 cdcJ*

2

( e- u-)

Reference [36], 600 °C

0.200 5.650 ±2.998 1.267

.300 2.767 ±0.922 -7.404

.400 0.519 ±0.692 -4.901

.500 -1.144 ±0.627 -11.632

.600 -2.786 ±0.295 -13.067

X O'cec \J

%2 (kcal/mol) 4W*2

( e- u -)

Reference [37], 800 °C

0.3883 -1.760 -15.109

.3901 -3.302 -17.591

.4159 -3.371 -43.882

.5102 -5.848 -5.555

.5780 -4.328 -10.208

.6781 -4.524 -7.307

.7441 -6.372 -15.689

.8393 -7.919 -6.220

.9042 -7.718 -8.680

.9828 -7.190 -9.737

Table 20. Excess properties of mixtures

CeClsd-X), KCl(x)

x A'-ceci J

xt (kcal/mol) scec \J

%2 ( e - u -)

Reference [37], 850 °C

0.1754 6.148 -57.867

.3204 -2.719 - 10.926

.5007 -4.167 - 16.578

.5203 -7.871 -4.115

.6695 -11.539 -4.152

.7340 -11.657 -1.045

.8422 -14.351 -7.142

.8889 - 14.360 -5.099

.9343 -13.338 -6.741

.9985 -13.287 -12.607

X A'-ceci J

%2 (kcal/mol)

Reference [38], 850 °C

0.251 -74.598

.487 - 36.685

.605 -37.702

.606 -38.938

.758 -27.502

.761 -29.183

.900 -22.839

.956 -19.913

.976 -19.737

37
Table 21. Excess properties of mixtures

CeCl3 (l — x), CaCl^x)

X txE

CeC \Jx

2 (keal/mol) SCeClJX l e - u -)

Reference [39], 850 °C

0.0947 61.495 52.556

.1980 22.590 — 64.464

.3988 4.887 - 19.509

.4936 3.625 -9.865

.5987 2.560 -7.977

.6677 1.914 -5.736

.7669 1.328 -3.180

.8989 1.005 -3.950

.9899 1.273 -6.157

TABLE 23. Excess properties of mixtures MgCL>(l — x), NaCl(x)

(The numbers following the ± in column 2 are precision

estimates.)

X EmcJx

~ (kcal/mol) 4gciJ

X

'Z

( e - u->

Reference [40] 700 °C

0.441 -0.048 ±0.521 49.381

.479 - .814 + 0.422 30.157

.597 -3.780 ±0.233 14.733

.621 -4.771 ±0.240 24.639

.677 -4.568 ±0.251 18.245

.758 -6.035 ±0.161 11.281

.778 -6.362 ±0.198 9.879

.764 -7.045 ±0.127 11.512

x /^Mgc

2 /-* 2 (kcal/mol)

Reference [41], 825 °C

Table 22. Excess properties of mixtures

MgCl2 (l — x), LiCl(x)

(The numbers following the ± in column 2 are precision

estimates.)

X fJL mkc^/*

2 (kcal/mol) 4«ci2 /* 2

( e - u-)

Reference [40], 700 °C

0.334 6.473 ±0.745 144.484

.447 3.913 ± .784 28.428

.553 3.249 ± .332 20.301

.634 2.082 ± .208 26.992

.707 0.332 ± .148 13.417

.773 .201 ± .208 15.762

.852 — .115 ± .115 8.764

.896 — .512 ± .115 7.747

.960 — 1.321 ± .106 10.534

0.256 0.000±0.775

.353 -5.627 ±0.408

.467 -5.963 ±0.233

.562 -7.601 ±0.161

.641 — 8.519±0.125

.675 — 8.124±0.111

.719 -8. 122 ±0.099

.811 -9. 123 ±0.076

.908 -8.731 ±0.062

.975 -7.469 ±0.053

Kiaci /* 1 -*)2 sLcAl ~ x?

(kcal/mol) (e.u.)

Reference [9], 850 °C

0.862 -1.579 -2.105

.853 -5.556 -0.463

.819 -5.793 .610

.784 -7.066 .642

.780 -6.818 -1.033

.744 -7.939 0.305

.720 -7.526 -1.020

.698 -7.895 -0.987

.681 -7.859 -1.473

.663 -8.099 -1.056

.638 -8.397 -1.145

.581 -8.542 -1.595

.526 -8.856 -1.335

.527 -9.522 -1.207

.448 -7.581 -1.969

.469 -9.043 -0.035

.387 -8.515 -1.064

38
TABLE 24. Excess properties of Mixtures MgCl2 (l — x), KCl(x)

(The numbers following the ± in column 2 are precision

estimates.)

X M-mkciJ

%2 (kcal/mol)

Reference [58, 41 ] , 800 °C

0.208 — 1 1.566 ± 1 .061 .290 — 10.694 ± 0.553

.437 - 14. 140 ±0.231

.531 -15. 605 ±0.161

.602 -14.349 ±0.138

.657 — 13.207 ±0.115

.675 -13.610 ±0.092

.748 — 17.517 ± 0.092

.832 -16. 180 ±0.069

.912 -13.946 ±0.046

.980 -12.287 ±0.046

.985 -11.853 ±0.046

* M-Mgci-A

2 (kcal/mol) s m«ciJ

x

'2

( e - u-)

Reference [40], 700 °C

0.378 1.873 ±0.692 29.838

.504 — 6.900±0.417 14.399

.596 -13.686 ±0.221 23.911

.610 — 13.313 ± 0.261 24.746

.702 -16.800 ±0.254 16.093

.712 — 17.796 ± 0.182 18.302

.789 — 15.704±0.127 19.371

Table 25. Excess properties of mixtures MgCbU — x), RbCl(x)

(The numbers following the ± in column 2 are precision

estimates.)

X ^mbci/*

2 (kcal/mol) s mc\Jx

~

< e - u -)

Reference [40] , 700 °C

0.410 -6.049 ±0.493 36.093

.523 -15.151 ±0.304 34.806

.590 -17.450 ±0.291 24.326

.657 -21.592 ±0.203 21.148

Table 26. Excess properties of mixtures

CaCl2 (l-x), NaCl(x)

X ^NaC|/( 1- *)2 (kcal/mol)

5NaC|/(l *)2

(e.u.)

Reference [9], 850 °C

0.981 0 -27.778

.939 0 -2.703

.870 -1.775 -3.550

.831 -3.217 -3.496

.761 -1.471 -2.802

.706 -2.083 -1.968

.656 -3.043 -1.522

.566 -2.919 -1.380

.484 -2.816 -1.427

.483 -2.881 -1.235

.465 -2.935 -1.328

.307 -2.728 -0.729

.222 -2.577 -.760

.133 -2.328 -1.011

.082 -1.958 -1.246

TABLE 27. Excess properties of mixtures

SrCl2 (l — x), NaCl(x)

X ^NaCl /< 1_ *)2 sNaC|/(

1- *)* (kcal/mol) (e.u.)

Reference [9], 850 °C

0.860 -1.020 2.551

.735 -0.114 -0.427

.700 -1.189 — .444

.597 -1.145 -.308

.583 -1.271 .345

.515 -1.139 .043

.500 -1.148 -.080

.412 - 1.059 .058

.346 -0.844 -.117

.285 -.683 -.293

.278 -.815 -.038

.193 -.654 -.246

.152 -.501 - .306

.097 -.724 -.343

39
TABLE 28. Excess properties of mixtures

BaCl2 (l — x), NaCl(x)

X PwaC. A1- *)2 4>ci /d-*)2

(kcal/mol) (e.u.)

Reference [9], 850 °C

0.903 0 1.064

.801 -.379 .505

.696 .043 .325

.691 .052 .105

.605 .032 .256

.587 .035 .176

.490 .115 .231

.381 .091 .209

.365 -.002 .198

.312 .070 .211 .277 .023 .191 .092 -.044 .146

TABLE 29. Excess properties of mixtures

PbCl2 (l — x), LiCl(x)

(The numbers following the ± in column 2 are precision

estimates.)

x ^PbcijJ

x

* (kcal/mol) s' cl Jx

2 (e.u.)

Reference [45], 600 °C

0.1600 0.812 ±3.964 -18.555

.3375 .606 ±0.809 .668

.5340 .413 ±0.291 -1.310

x pthPbC \ Joe

2 (kcal/mol)

Reference [46], 600 °C

0.2030

.2840

.2990

.3270

.4030

.4970

.4980

.5920

.5950

0.375

-.930

-1.615

-1.508

.116

-.138

-.235

-.140

-.232

Table 30. Excess properties of mixtures PbCL(l — x), NaCl(x)

(The numbers following the ± in column 2 are precision

estimates.)

x PpbciJ*

1 (kcal/mol)

Reference [48], 600 °C

0.500 -0.722

X PpbciJx

’2 (kcal/mol) 5 PbCl2 /X"

( e- u-l

Reference [45], 600 °C

0.100 8.532 ±8.302 -13.610

.250 -1.033 ±1.033 -4.870

.400 -1.211 ±0.461 -0.029

.500 -0.830 ±0.442 -2.721

X P-PbciJ

xl (kcal/mol)

Reference [46], 600 °C

0.3030 -1.615

.3970 -2.331

.4490 -2.052

X P-Pbcijj/*

2 (kcal/mol) 5

PbClJ

x

~

( e - u-)

Reference [44], 600 °C

0.500 — 0.517 ±0.166 13.568

.700 -.978 ±0.018 1.016

40
Table 32. Excess properties of mixtures

PbCl2 (l — x), RbCl(x)

TABLE 31. Excess properties of mixtures PbCl2 (l — x), KCl(x)

(The numbers following the ± in column 2 are precision

estimates.) x ^bcJ*2 (kcal/mol)

x /^PbciJx2 (kcal/mol) s

pbci J

x

'2

( e - u-)

Reference [49], 600 °C

0.050 -54.423 ±14.759 -254.600

.100 - 22.830 ± 5.535 -87.860

.200 -2.191 ± 0.922 -125.795

.300 — 9.173 ± 0.666 -50.759

.400 — 11.819 =b 0.231 -38.482

X IXpbcJx

2 (kcal/mol) S

PbCl2

/'*' 2

( e - u‘)

Reference [45], 600 °C

0.200 — 2.191 ±2.191 -10.837

.300 -6.355 ±1.485 - 14.323

.400 -5.592 ±0.777 -11.299

.500 -5.350 ±0.369 -5.359

.600 — 5.541 ± 0.256 -4.458

Reference [46], 600 °C

0.2000 -10.614

.2510 -6.534

.3330 -6.554

.3980 -6.553

.4980 -6.894

.5970 -7.506

Table 33. Excess properties of mixtures

PbCl2 (l —x), CsCl(x)

(The numbers following the ± in column 2 are precision

estimates.)

X P-pbci Jx

2 (kcal/mol) 5

Pbci2 /* 2

( e - u*)

Reference [44], 650 °C

0.500 -7.315 ±0.055 10.856

.700 -9.393 ±0.046 5.704

x P-PbciJ

x

'2 (kcal/mol)

Table 34. Excess properties of mixtures

PbCl2 (l — x), CaCl2 (x)

Reference [46], 600 °C

0.2030 -5.222

.2710 -2.956

.3350 -4.789

.4000 -4.403

.5010 -5.116

.5060 -4.912

.5940 -5.318

.6560 -5.365

x ^PbciJ

x2 (kcal/mol) 5£bci 2 /*2

( e- u-)

Reference [44], 600 °C

0.500 -5.202 ±0.129 -1.392

.700 -5.601 ±0.113 6.392

X fXpbciJx

2 (kcal/mol)

Reference [45], 650 °C

0.200 2.191

.400 1.123

Table 35. Excess properties of mixtures

PbCl2 (l-- x), SrCl2 (x)

X Mpbt i 2 /* 2 (kcal/mol)

Reference [45], 650 °C

0.200 2.191

.400 1.543

41
TABLE 36. Excess properties of mixtures

PbCl2 (l — x), BaCl2 (x) Table 38. Excess properties of mixtures ZnCl2 (l — x), LiCl(x)

X Mpbci2 /* 2 (kcal/mol)

Reference [45], 650 °C

0.200 1.038

.400 -.187

Table 37. Excess properties of mixtures

PbCl2 (l — x), ZnCl2 (x) (The numbers following the ± in column 2 are precision

estimates.)

X P-fnciJ*

1 (kcal/mol)

Reference [58], 550 °C

0.2990 4.953

.4030 3.210

.5040 2.887

.6050 2.634

.6590 -2.959

.7000 -4.453

.7990 -2.820

.8940 -1.058

.9530 0.533

x /^pbci/*

2 (kcal/mol) sE

PbCiJx

2 (e.u.)

Reference [50], 500 °C

0.145 — 5.710±2.195 -55.233

.312 -2.537 ±0.475 2.560

.405 -2.502 ±0.337 3.079

.510 — 2.350±0.178 1.126

.699 -1.746 ±0.085 5.149

x M'PbciJ

x2 (kcal/ mol)

Reference [51], 500 °C

0.242 -1.865 ±0.786

.385 — 1.931 ±0.311

.486 -1.763 ±0.196

.586 -1.520 ±0.134

.632 — 1.500 ±0.115

.809 -.870 ±0.071

Table 39. Excess properties of mixtures ZnCl2 (l — x), NaCl(x)

(The numbers following the ± in column 2 are precision

estimates.)

X jufnc,,/*

2 (kcal/mol) 5fnClJX1

( e- U-^

Reference [59], 550 °C

0.100 -3. 920± 11.991 -147.36

.200 - 0.231 ± 2.883 -31.822

.300 — .743 ± 1.485 -36.153

.400 — 4.151 ± 0.980 -6.140

.500 - 5.756 ± 0.498 + 2.758

42
rABLE 40. Excess properties of mixtures ZnCl2 (l— x), KCl(x)

Table 41. Excess properties of mixtures

ZnCl2 (l — x), RbCl(x)

The numbers following the ± in column 2 are precision (The numbers following the ± in column 2 are precision

estimates.) estimates.)

x /u,|nC] lx2 (kcal/mol) x /

JLztm.Jx2 (kcal/mol)

Reference [60], 550 °C

0.102 -49.446

.204 -20.955

.300 -10.428

.395 - 10.407

.487 -15.035

.528 -12.969

.591 -13.112

.660 -21.778

.700 -19.417

.720 - 18.492

X £tfnc l2 /*2 (kcal/mol) 5ZnClJ

X

"

l e- u-)

Reference [59 1, 550 CC

0.100 33.438 ±23.522 -2097.81

.200 — 19.025 ± 10.031 560.485

.300 -3.561 ± 1.333 -47.940

.400 -6.745 ± 0.749 4.583

.500 - 10.516 ± 0.480 14.786

.600 -14. 157 ± 0.743 -9.698

Reference [60], 550 °C

0.105 -71.697

.209 -31.293

.313 - 15.404

.400 -25.034

.500 -19.814

.610 -27.963

.688 -22.671

X A«fnC1J

%2 (kcal/mol) 4nClJ

%2

Reference [61 1, 550 °C

0.211 -2.020 ±0.623 34.928

.264 — 4.135±0.397 16.808

.315 -4.790 ±0.233 28.918

.366 -6.040 ±0.207 18.741

.392 -7.548 ±0.270 16.429

.453 -9. 102 ±0.090 21.173

.526 -13.251

335-493 0-69—4 43
TABLE 42. Excess properties of mixtures

ZnCl2 (l — x), CsCl(x)

Table 45. Excess properties of mixtures AgBr(l — x), KBr(x)

x MznciJ

%2 (kcal/mol)

Reference [62], 600 °C

0.216 -31.969

.300 -22.574

.409 - 13.440

.418 -18.520

.432 -20.070

.490 - 16.348

.588 -11.094

.650 -37.333

.685 -41.972

.700 -58.375

.740 - 165.650

.750 - 166.801

Table 43. Excess properties of mixtures

AgBr(l — x), LiBr(x)

(The numbers following the ± in column 2 are precision

estimates.)

X U-aubi-/*

2 (kcal/mol) 5W*2

< e- u-)

Reference [63], 550 °C

0.4063 1.801 ±0.055 -0.587

.5914 1.667 ±0.039 -.310

.7452 1.965 ±0.030 -.507

.8900 1.861 ±0.012 -.748

Table 44. Excess properties of mixtures

AgBr(l-x), NaBr(x)

(The numbers following the ± in column 2 are precision

estimates.)

X P-AKBr /* 2 (kcal/mol) 5 A«Br/*

2

( e - U‘)

Reference [67], 600 °C

0.2514 1.605 ±0.145 2.737

.3995 1.061 ±0.060 1.784

.4870 1.040 ±0.039 10.470

X /“•akbi-/*

2 (kcal/mol) sEakJx

'2

( e - u-)

Reference [68], 600 °C

0.2000 -0.577 11.300

.3995 -1.372 0.058

.5498 -1.480 .099

.6462 -1.540 1.353

TABLE 46. Excess properties of mixtures AgBr(l— x), RbBr(x)

(The numbers following the ± in column 2 are precision

estimates.)

X P-akbA

2 (kcal/mol) 5W*2

< e - u-)

Reference [65], 550 °C

0.2530 -1.946 ±0.180 0.180

.4040 — 2.783±0.510 -3.561

.5330 -2.606 ±0.032 -0.787

.6480 -2.608 ±0.028 -.533

TABLE 47. Excess properties of mixtures AgBr(l — x). PbBr2(x)

(The numbers following the ± in column 2 are precision

estimates.)

X M'Akbi-/*

2 (kcal/mol) 5W*2

( e- u-)

Reference [66], 550 °C

0.200 — 0.173±0.231 6.572

.300 .025 ±0.101 -0.589

.400 .028 ±0.058 .404

.500 .009 ±0.037 .738

.600 .090 ±0.032 -.974

.700 .141 ±0.018 -.783

.800 .159±0.018 -.267

.900 .168±0.014 -.649

44
rABLE 48. Excess properties of mixtures CdBr2 ( 1 — x), KBr(x)

X P-cdBrs/*

2 (kcal/mol)

Reference [69], 597.5 °C

0.150 - 19.269

.300 - 10.197

.523 - 8.777

.600 - 9.409

.700 - 10.698

.800 - 12.423

Table 49. Excess properties of mixtures

PbBr2 (l — x), NaBr(x)

X M'PbB r.Jx2 (kcal/mol)

Reference [73], 589 °C

0.200 - 1.153

.300 - 2.075

.400 - 2.018

.500 - 2.075

.600 - 2.299

.700 - 2.029

Table 50. Excess properties of mixtures

PbBr2 (l — x), KBr(x)

The numbers following the ± in column 2 are precision

estimates.)

X McbBr (kcal/mol) S PbBrJ

X

*

( e - U‘)

Reference [71], 550 °C

0.1800 — 57.082 ± 12.669 995.525

.2300 - 37.402 ± 7.760 607.372

.3300 - 19.885 ± 3.770 292.498

.3800 — 17.136 ± 2.843 232.299

.4800 — 16.274 ± 1.783 124.049

.5500 - 16 . 299 ± 1.356 102.684

.6500 - 16.620 ± 0.971 65.787

.6800 - 16.387 ± .888 43.767

Table 51 . Excess properties of mixtures

PbBr2 (l — x), ZnBr2 (x) (The numbers following the ± in column 2 are precision

estimates.)

X P-pbBrJ

x

* (kcal/mol) 5 pbBr

2 /* 2

( e - u-)

Reference [70], 500 °C

0.0980 — 1.201 ± 12.492 240.937

.2060 — .217 ± 2.827 49.656

.2960 — .263 ± 1.474 30.115

.3960 — , 030 ± 0.823 16.281

.5140 . 131 ± .489 9.671

.6080 .175 ± .325 8.552

.7120 .267 ± .238 7.866

.7900 . 274 ± .208 8.510

.8000 . 288 ± .194 8.219

Table 52 . Excess properties of mixtures Agl(l — x), KI( x) (The numbers following the ± in column 2 are precision

estimates.)

X Pahi/*

2 (kcal/mol) se

aJx2 (e.u.)

Reference [75], 600 °C

0.1 - 2.444 ± 3.459 - 9.45

.2 - 3.580 ± 0.876 - 2.423

.3 - 2.988 ± 0.392 - 1.460

.4 - 2.385 ± 0.219 - 0.576

.5 — 1 . 830 ± 0.138 .028

.6 - 1.669 ± 0.092 .705

.7 - 1.477 ± 0.069 .292

Table 53. Excess properties of mixtures AgBr(l — x), AgCl(x)

X |U,£

AgBrlx

2 (kcal/mol) s^Brlx'2 (e.u.)

Reference [64], 600 °C

0.200 4.439 ± 0.173 8.012

.400 2.391 ± 0.044 1.456

.600 1 . 730 ± 0.018 - 1.019

.800 2.262 ± 0.012 - 2.220

45
Table 54. Excess properties of mixtures Agl( 1 — x). AgCl(x)

(The numbers following the ± in column 2 are precision

estimates.)

X pbfnl lx2 (kcal/mol) sfSI lx2 (e.u.)

Reference [76], 600 °C

0.200 0.455 ±0.876 -2.423

.400 .497 ±0.219 -1.297

.500 .384 ±0.138 -0.434

.600 .404 ±0.092 .064

Table 55. Excess properties of mixtures Agl( 1 — x), AgBr(x)

X E-amI*

2 (kcal/mol) sljx2 (e.u)

Reference [76], 600 °C

0.200 2.185 ±0.876 0.460

.400 1.074 ± 0.219 -.576

.500 1.122 ±0.138 -.434

.600 1.086 ±0.092 .064

Table 57. Excess properties of mixtures

NaBr(l — x). NaCl(x)

X ^xaiiA

2 (kcal/mol) SLJ*

2

( e- u->

Reference [9], 800 °C

0.103 0.943 -0.755

.204 .433 -.385

.295 .402 -.276

.371 .363 -.262

.435 .365 -.243

.483 .429 -.244

.55 .231 -.221

.7 .408 -.286

(The numbers following the ± in column 2 are precision

estimates.)

x ^NaBi-/*

2 (kcal/mol)

Reference [84], 800 °C

0.200 0.657± 1.153

.300 .612 ±0.507

.500 .424 ±0.184

.600 .438 ±0.138

Table 56. Excess properties of mixtures KBr(l—x), KCl(x)

x E

EKBJx- (kcal/mol) s kbJx1 (e.u.)

Reference [9], 800 °C

0.098 1.042 -1.458

.193 0.806 -0.995

.284 .496 -.645

.298 .811 -.586

.384 .678 -.508

.396 .574 -.478

.414 .817 -.694

.427 .713 -.653

Table 58. Excess properties of mixtures

PbBr>(l — x). PbCb(x)

(The numbers following the ± in column 2 are precish

estimates.)

X ^PbBrJ*

2 (kcal/mol) s PbBr/*

2 (e - u ->

Reference [72], 500 °C

0.200 -5.938 ±0.807 21.562

.400 — 2.998±0.173 11.415

.500 -2.527 ±0.092 6.190

.550 -2.790 ±0.122' 3.812

46
8. References

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31 (1954).

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Populaire Roumaine, 2, 251 (1957).

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Chem. Soc. 58, 1848 (1936).

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Acad. Rep. Populaire Roumaine 7, 107 (1959).

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33, 29 (1965).

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(1965).

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295 (1959).

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[33] Dijkhuis, C. G. M., An Investigation of Molten Cadmium

Halide-Alkali Halide mixtures by emf measurements,

Thesis, University of Amsterdam (1964).

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11, 1607(1966).

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(1929).

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(U.S.S.R.) 26, 321 (1953).

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Sci. 79, 878 (1960).

[38] Neil, D. E., Thermodynamic Properties of Molten Chloride

Solutions, Thesis, Rensselaer Polytechnic Institute, Troy, N.Y. (1959). Dissertation Abstr. 20, 2591 (1960).

[39] Senderoff, S., Mellors, G. W., and Bretz, R. I., J. Electro- chem. Soc. 108,93(1961).

[40] Markov, B. F., Delimarskii, Yu. K., and Panchenko, I. D., Zh. Fiz. Khim. 29 , 51 (1955).

[41] Neil, D. E., Clark, H. M., and Wiswall. R. H. Jr., J. Chem.

and Eng. Data 10, 21 (1965).

[42] Bruneaux, M., Ziolkiewicz, S., and Morand, G., Compt.

Rend. 257, 3591 (1963).

[43] Bruneaux, M., Ziolkiewicz, S., and Morand, G., J. Chim.

Phys. 61, 1215 (1964).

[44] Hagemark, K., and Hengstenberg, D., J. Chem. and Eng. Data 11, 596 (1966).

[45] Lantratov, M. F., and Alabyshev, A. F., Zh. Prikl. Khim. 26,

263 (1953). Eng. Transl.: J. Appl. Chem. (U.S.S.R.) 26,

235 (1953).

[46] Markov, B. F., Delimarskii, Yu. K., and Panchenko, I. D., Zh. Fiz. Khim. 28, 1987 (1954).

[47] Markov, B. F., Delimarskii, Yu. K. , and Panchenko, I. D.,

J. Polymer Sci. 31, 263 (1958).

[48] Suskii, L., Zh. Fiz. Khim. 30, 1855 (1956).

[49] Hildebrand, J. H., and Ruhle, G. C., J. Am. Chem. Soc. 49,

722 (1927).

[50] Wachter, A., and Hildebrand, J. H., J. Am. Chem. Soc. 52,

4655 (1930).

[51] Nakamura, Y., and Brenet, J., Compt. Rend. 262C, 673

(1966).

[52] Alabyshev, A. F., Lantratov, M. F., and Morachevskii,

A. G., Izvest. V.U.Z.M.V.O.S.S.S.R., Khim Tekhnol. 3,

649 (1960).

[53] Benz, R., J. Phys. Chem. 65, 81 (1961 ). [54] Benz, R., and Leary, J. A., J. Phys. Chem. 65, 1056 (1961).

[55] Delimarskii, Yu. K., and Markov, B. F., Electrochemistry

of Fused Salts (R. E. Wood, transl.). The Sigma Press, Washington, D.C., U.S.A. (1961).

[56] Takahashi, M., J. Electrochem. Soc. Japan 28, E-117

(1960).

[57] Marsland, D. B., Dissertation Abstr. 19, 1222 (1958).

[58] Markov, B. F., and Volkov, S. V., Ukr. Khim. Zh. 30,

341 (1964).

[59] Lantratov, M. F., and Alabyshev, A. F., Zh. Prikl. Khim.

27, 722 (1954). Engl. Transl.: J. App. Chem. (U.S.S.R.),

27, 685 (1954).

[60] Markov, B. F., and Volkov, S. V., Ukr. Khim. Zh. 30,

545 (1964).

[61] Markov, B. F., Zh. Fiz. Khim. 31, 2288 (1957).

[62] Markov, B. F., and Volkov, S. V., Ukr. Khim. Zh. 30,

906 (1964).

[63] Salstrom, E. J., and Hildebrand, J. H., J. Am. Chem. Soc. 52,4650 (1930).

[64] Murgulescu, I. G., and Marchidan, D. I., Rev. Chim. Acad.

Rep. Populaire Roumaine 3, 47 (1958).

[65] Salstrom, E. J., J. Am. Chem. Soc. 54, 4252 (1932).

[66] Salstrom, E. J., J. Am. Chem. Soc. 54, 2653 (1932).

[67] Salstrom, E. J., J. Am. Chem. Soc. 53, 1794 (1931).

[68] Salstrom, E. J., J. Am. Chem. Soc. 53, 3385 (1931).

[69] Lantratov, M. F., and Shevlyakova, T. N., Zh. Prikl. Khim.

4, 1065 (1961).

[70] Salstrom. E. J., J. Am. Chem. Soc. 55, 1029 (1933).

[71] Lantratov, M. F., and Shevlyakova, T. N., Zh. Neorgan.

Khim. 4, 1153 (1959).

[72] Salstrom, E. J., and Hildebrand, J. H., J. Am. Chem. Soc. 52, 4641 (1930).

[73] Lantratov, M. F., and Shevlyakova, T. N., Zh. Neorgan.

Khim. 6, 192 (1961).

[74] Sternberg, S., Adorian, I., and Galasiu, I., J. Chim. Phys.

62, 63 (1965).

[75] Sternberg, S., Adorian, I., and Galasiu, I., Electrochim. Acta 11, 385 (1966).

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Chim. 11, 581 (1966).

[77] Ketelaar, J. A. A., and Dammers-de Klerk, Mrs. A. A., Rec. Trav. Chim. 83, 322 (1964).

[78] NBS Circular 500, Selected Values of Chemical Thermodynamic Properties, United States Government Printing

Office, Washington, D.C. (1952). 47
[79] Landolt-Bornstein, Zahlenwerke und Funktionen, Vol. 2,

f Part 4, Springer Verlag Berlin (1961).

[80] Kelley, K. K., Contributions to the Data on Theoretical

Metallurgy, Vol. 10, Bureau of Mines, United States Government Printing Office, Washington, D.C. (1949).

[81] Altshuller, A. P., J. Phys. Chem. 61, 251 (1957).

[82] Forland, T., and Ostvold, T.. Acta Chem. Scand. 20 , 2086

(1966).

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[84] Sternberg, S.. and Herdlicka. C.. Rev. Roumaine Chim.. 1 1

,

29(1966).

[85] Dijkhuis, Chr. G. M., and Ketelaar. J. A. A.. Electrochim.

Acta, 12, 795 (1967).

9. Compound Index

Page

AgBr 5, 6, 30 — AgCl 6, 24, 25, 28, 45 — KBr 6, 21, 22, 28, 44 — LiBr 6, 20, 21, 22, 28, 44 — NaBr 6, 21, 22, 28, 44 — PbBr2 6, 21, 22, 28, 44 — RbBr 6. 21, 22, 28, 44

Page

Lil 35 MgCb 4.5.30 — KC1 6, 13, 14, 27, 39 — LiCl 6, 12, 13, 27, 38 — NaCl 6, 12. 13, 27, 38 — RbCl 6, 13, 14, 39

AgCl 3, 4, 28, 29 — KC1 6, 7, 8, 27, 36

-LiCl 6, 7, 8, 27, 35

-NaCl 6, 7, 8, 27, 36

-PbCl2 6, 7, 8, 27, 36

Agl 6. 34

-AgBr 6, 25, 28. 46

-AgCl 6, 25, 28, 46 — KI 6, 24, 26, 28, 45

AgNOa 6

BaCl2 — NaCl 6, 14, 15, 27, 40

BeCl2 4, 29 — NaCl 4, 6, 9

CaCl2 — NaCl 6, 14, 15, 27, 39

MnCl, 5 — KC1 6. 14 -NaCl 6, 14

NaBr. -NaCl..

NaCl— MgCL

26, 35

6, 25. 28. 46

3, 12, 14, 35

3 NaF 35

Nal 35

PbBr. 5. 6, 22, 23. 34 -KBr 6, 23. 28. 45 -NaBr 6. 22, 23, 27, 45 -PbCU 6,27,28.46 — ZnBr> 6. 23. 24, 28. 45 CdBr2 ... -KBr

5, 22, 33

6, 22, 28, 45

CdCl- BaCU — KC1.. -NaCl

4, 5, 9. 30

6, 9, 10, 27, 37

6, 9, 10, 27, 37

6, 9, 10, 27, 37

Cdl2 — Nal 6, 24, 28

CeCl:! — CaCls — KC1.. -NaCl

4

6, 11, 12, 27

4, 6, 11, 12, 27, 37

6, 9, 11, 12, 27, 38

KBr— KC1

26, 35

6, 26, 28, 46

KC1 35

KF 35

KI 35

LiBr 35

LiCl 35

LiF 35

PbCl, 5, 18, 31 — BaCL 6. 18. 28, 42 — CaCL 6. 18. 28. 41 — CsCl 6. 17, 28. 41 — KC1 6, 16. 17,27, 41 -LiCl 6. 15, 16, 27, 40. 42 -NaCl 2. 6, 16. 17, 27, 40 — RbCl 6. 16. 17, 28. 41 — SrCL 6. 18. 28, 41 — ZnCL 6. 16, 18. 28, 42 PbL-Nal 6, 24, 28 PuCL 5, 18 — KC1 5. 6. 18 -NaCl 5.6. 18 SrCL-NaCl 6. 14. 15. 27, 3<

ZnCl 5, 19, 31 — BaCL 6. 20, 21 -CsCl 6.20,* — KC1 6, 19, 20. 28, 4i -LiCl 6. 18, 19. 21 -NaCl 6. 19. 20. 28. 4! -RbCl 6.20.4:

48
Molten Salts: Volume 2

Section 2. Surface Tension Data

G. J. Janz,* G. R. Lakshminarayanan,*

R. P. T. Tomkins,* and J. Wong*

Data on the surface tensions of single salt melts have been systematically collected and evaluated. Results are given for 107 inorganic compounds over a range of temperatures where available. Key words: Critically evaluated data; molten salts; surface tension.

Contents

Page

1. Introduction 49

2. Symbols and units 50

3. Theory and practice 50

3.1. Introduction 50

3.2. Maximum Bubble pressure method 50

3.3. Detachment methods 51

a. Wilhelmy slide plate method 51

b. Pin method 51

c. Maximum pull on cylinder method 52

d. Ring method 52

3.4. Capillary rise method 52

3.5. Methods based on the shape of static drops on

bubbles 53

a. Sessile bubble method 53

b. Pendent drop method 53

3.6. Summary 54

4. Treatment of surface tension data 54

4.1. Statistical analysis of data 54

4.2. Selection of the best values 54

4.3. Estimation of uncertainty 55

4.4. Preparation of the tables 55

5. Discussion 55

Fluorides 55

Chlorides 57 Bromides 62

Iodides 64

Oxides 65

Sulfides 66

Metaborates 66

1. Introduction

This work was undertaken to meet the need for

the critical assessment of the surface tension data

of inorganic compounds as single-salt melts. Results are given for some 107 compounds for which

data were published before December 31, 1966.

The order of listing the salts in this compilation

follows a classification by anions, i.e. monatomic

anions: Fluorides (9), Chlorides (22), Bromides (12),

‘Molten Salts Data Center. Rensselaer Polytechnic Institute, Troy. N.Y. 12180.

Page Carbonates 66

Nitrates 67

Nitrites 70

Silicates 70 Metaphosphates 71 Sulfates 72 Molybdates 74 Tungstates 74 Miscellaneous 74

6. Numerical values of surface tension 78

Fluorides 78 Chlorides 80

Bromides 85

Iodides 87 Oxides 90

Sulfides 91 Metaborates 92 Carbonates 92

Nitrates 93

Nitrites 95

Silicates 96

Metaphosphates 97

Sulfates 99

Molybdates 101 Tungstates 102 Miscellaneous 102

7. Cumulative table of temperature dependent equations... 104

8. References 109

9. Compound index 110

Iodides (7), Oxides (8), Sulfides (2); polyatomic

anions: Metaborates (3), Carbonates (3), Nitrates

(11), Nitrites (2), Silicates (5), Metaphosphates (7), Sulfates (5), Molybdates (4), Tungstates (2). Additional salts are given as Miscellaneous. The number

of salts is indicated in parentheses after each

anionic group. The order within an anionic group is given in an index list which precedes the tables of

numerical values for each group. In the bibliography,

those references having data of molten salt mixtures

are marked with an asterisk.

49
2. Symbols and Units

The temperature dependence of the surface ten- sion has been expressed by linear or quadratic

equations:

y = a + bt

y— a + bt+ ct

2

where a, b , and c are constants. Unless otherwise

stated, the units in this compilation are:

Temperature t , °C; 0 °C = 273.15 °K [22]

Surface Tension y, dyne cm-1 a,b

3. Theory and Practice

3.1. Introduction

Some 200 surface tension determinations have

been made on 107 single-component salt melts

using eight experimental techniques. The most

versatile method, and one that is applicable to these

molten systems at elevated temperatures, is the

method of maximum bubble pressure; 75 percent

of the total determinations on the 107 molten salts

have been made by this technique. Other methods,

in descending percentages of application are: Wilhelmy slide plate, capillary rise, maximum pull on cylinder, pin, pendant drop, ring, and sessile

bubble. The percent application, tabulated in table 1, summarizes the fraction of the total determinations made by each technique.

Table 1 . Classification of the molten salt surface tension techniques by the fraction of the total determinations made

by each technique as percent application

Method Percent

application

Method Percent

application

Maximum bubble pressure 74.6 Pin method 3.2 Wilhelmy slide plate 7.2 Pendant drop 2.5 Capillary rise 5.7 Ring method 2.0 Maximum pull on cylinder 4.2 Sessile bubble 0.6

3.2. Maximum Bubble Pressure Method

The maximum bubble pressure method of determining the surface tension of a liquid, suggested

by Simon [81]** in 1851, was first applied to molten

salt systems in 1917, by Jaeger [46]. It involves

the very slow formation of a bubble at the tip of

a capillary immersed in the melt and the subsequent determination of the maximum pressure

in the bubble at the very instant it bursts. Cantor [55] discussed the theory of bubble formation;

his equation for the maximum bubble pressure [55,

56] is:

------- f-V

2 L 3h 6 \h) ( 1 )

where y= surface tension of the melt (dyne cm-1

),

a When y is treated as a free energy per unit area, it is given the unit, erg cm-2

; this is dimensionally identical to dyne cm-1

. h system:* For conversion to the SI *

1 dyne cm-1 = 1 X 10~3 Nm_l

*The NBS Office of Standard Reference Data, as administrator of the National Standard Reference Data System, has officially adopted the use of SI units for all NSRDS publications, in accordance with NBS practice. This publication does not use

SI Units because contractual commitments with the author predate establishment of

a firm policy on their use by NBS. The appropriate conversion factor is found above for

y. The NBS urges that specialists and other users of data in this field accustom themselves to SI Units as rapidly as possible. **Figures in brackets indicate the literature references on page 109.

r= radius of the capillary (cm), p= maximum

pressure difference between the inside and outside

of the bubble at the level of the end of the tip

(dyne cm 2

), h the height (cm) gip-p')

of a column of the melt equivalent to pressure

p, p= density of the melt being measured (gem-3

), p ' = density of the gas (gem-3

), and g— acceleration

of gravity.

Sugden [52a] showed that the Schrbdinger approximation [56] is valid for values of < 0.2. For

0-2. the method of successive approximations and the Sugden tables should be used.

The thorough investigations of Hoffman [82] and

Tripp [83] showed that the mathematical theory

is in accord with experiment only if the bubbles

are formed slowly (one bubble per 30 or 60 s). When

the rate of bubble formation is high, the situation

is more complex and not readily amenable to theoretical treatment.

The most extensive series of studies by this

method are those of Jaeger [46] (51 salts) and Ellis

et al. [34-39] (20 salts). The method is well suited

for molten salts with surface tensions from 50 to

50
150 dyne cm-1

, and for measurements from room

temperature to 1600 °C.

This method does not lend itself well for studies

of viscous melts (e.g. ZnCh) or molten salts having

high vapor pressures [31a]. The formation of bubbles

may be erratic in such melts. If a series of smaller

bubbles is formed on the “burst’', the pressure

drop will be stepwise in the system. Again, the

bubble may not burst even though pressure is increased and decreased; another possible occur- rence is that response to the bubble burst is slow

and abnormally small in melts of this type.

Some of the experimental features that distinguish the high-temperature application of this

technique from the ambient-temperature applications are as follows:

(a) Certain melts may be quite corrosive. The

radius of the capillary tip should be checked, preferably after each experiment. The time and area

of contact of the melt with various components of

the surface tension assembly also should be

minimized.

(b) Visual observations of the melt are frequently

not possible. The contact of the capillary tip with

the surface of the melt may have to be detected by

indirect techniques (e.g. electrical contact).

(c) There may be a cooling effect at the surface

of the melt during the formation and release of the

bubbles from the capillary tip. Preheating of the

inert bubbling gas to the temperature of the meas- urement has been recommended by Jaeger [46]

and Semenchenko and Shikhobalova [4]. For slow

bubbling rates. Dahl and Duke [31a] found this precaution unnecessary.

3.3. Detachment Methods

A “detachment method’’ is any method in which

the force required to detach an object from the sur- face of the liquid is measured. The maximum pull

just before the object is detached from the surface

is equated to the weight of the object plus yL, where

L is the total perimeter introduced into the melt.

The weight of the liquid which has been raised

above the liquid surface, at the moment of detachment, is thus given by the total tension that its sur- face will support if the contact angle is zero. The

following four methods are molten salt surface

tension detachment methods.

occurs. The surface tension is calculated by the

expression:

^tot=rpiate + 2y(L + *) (2)

where L = width of the slide, x — thickness of the

slide, and Wtot , Wp \ ate = observed weights at the mo- ment of detachment and before dipping into liquid,

respectively. End effects are assumed negligible.

This technique has been estimated to be accurate

to within ±0.1 percent for room temperature meas- urements of aqueous and organic liquids [57].

Bertozzi [26, 45] has applied this technique to molten alkali metal nitrates (300-600 °C) and halides

(600—900 °C) with an uncertainty of ±0.6 percent.

(b) Pin Method

This was introduced by Janz and Lorenz [48, 49]

to measure simultaneously the surface tensions and

densities of molten alkali nitrates and carbonates;

it has also been used by Morris, McNair and

Koops [24] for the molten molybdates. The surface

tension detachment pin is part of an Archimedean

density bob. The weight is noted at room temperature and again at the working temperature after

temperature equilibrium has been reached, so as

to correct for the change in the bouyant force of

air at higher temperatures. The crucible with the

melt is then raised until the pin just contacts the

melt; at this point the contact weight (Wc ) and the

relative crucible height are noted. The crucible is now lowered and the maximum “puli’’ at the mo- ment of detachment is measured. The break-point

weight (Wb) and the final rest weight (Wr ) are noted.

The surface tension pull of the bob is 27rry dynes,

where r and y have their conventional significance;

this is equal to the difference between the break and

the rest weights, i.e. gWd — g( Wb — WV) assuming

zero angle of contact at the break-point. It follows

that the surface tension is given by:

gWd AWd (3)

where the constant A is a characteristic of the pin

dimensions. If the radius of the pin at any temperature t °C is expressed as:

(a) Wilhelmy Slide Plate Method r = r0 ( 1 + aAt ) (4)

In the Wilhelmy application [84] of the above

principle, the maximum pulling force is determined

for the detachment of a thin platinum plate from the

liquid surface. For a straight edge, this force is proportional to the surface tension of the liquid. The

plate is suspended from one arm of a balance and

is dipped into the liquid: the melt container is then

lowered until detachment occurs. The “pull" on

the balance arm is noted at the instant detachment

where ro = radius of the pin at the calibration temperature (to). a = the coefficient of linear expansion

of the pin material, and At = {t — to), eq (3) becomes:

ApW d 7 ~l±aAt ( 5)

where the constant Ao= , ^

. The value of Ao can

277T0

51
be gained if ro is known or by the use of calibration

liquids of accurately known surface tensions. Densities can be gained as part of the same experiment

in the conventional manner by complete immersion

of the Archimedean bob when the surface tension

measurements have been completed.

(c) Maximum Pull on Cylinder Method

This is a modification of the ring method, the

ring being replaced by a vertical hollow cylinder.

It has been widely used at ambient and high temperatures. An equation similar to that developed by

Harkins, Young and Cheng [65] for the ring method

is used to calculate the surface tension, i.e.:

where /? = the mean radius of the cylinder (cm),

F= a dimensionless factor depending on R:i /V

and R/xV= (M/pi) is the volume of liquid held up

by the cylinder (cm3

), and jc = the thickness of

the cylinder wall (cm).

In using this method for determining the sur- face tensions of silicate slags. King found [58] that

the values of the F factors for a cylinder were

not the same as for a ring. Liquids of known sur- face tensions were used to gain correction factors

and thus the calibration curve applicable to the

cylinder (/? = i in) was found. Bradbury and Maddocks [27a, 27b], using a cylinder also with R = \

in, reported a somewhat different calibration curve

for F(/?3 /F. ) No explanation was advanced for the

difference in the two calibration curves. The differ- ence may be attributed, in part, to the neglect of

the dimensionless variable R/x in the preceding

calibration; differences in the thickness of the

walls of the cylinders used by King [58] and by

Bradbury et al. [27a, 27b] would also contribute

but the information is insufficient to assess this

further.

The effect of the contact angle, 6 , on the maximum pull on the cylinder was investigated by King;

it was negligible unless 6 > 40°.

(dr Ring Method

A thorough discussion of the theory and experimental aspects of this method at ambient temperature is given by Harkins elsewhere [51]. The

principles of this method were developed largely in

two papers by Harkins, Young and Cheng [65],

and Harkins and Jordan [66]. Callis, van Wazer, and

Metcalf used this technique for sodium metaphosphate and mixtures of Na2 0 and P2 05 at high

temperatures, with due cognizance of the fac- tors [66] necessary for the calculation of surface

tensions. A comparison of the surface tension data

for sodium metaphosphate by this method [28,

88] and two other techniques, i.e., the maximum

pull on cylinder [27] and the maximum bubble

pressure method [9, 46] is given in figure 1. (Percent

departure is defined on p. 55). The percent departures are calculated relative to the data of

Owens and Mayer [88] as the reference.

600 800 1000 1200 1400 Temp (°C)

Figure 1. Comparison of percent departure of the data for NaPO:i . — Owens and Mayer (1964) [88] # Jaeger (1917) [46] Callis, van Wazer and Metcalf (1955) [28] O Bradbury and Maddocks (1959) [27b] A Sokolova and Voskresenskaya (1963) [9]

3.4. Capillary Rise Method

The capillary rise method is the simplest for

closed systems (a requirement for low-melting

salts of high volatility, e.g., UF« [50], ZnCL> [38]

GaCl3 [42-44] ); it is best suited for systems where

visual observation of the melt is possible. The principles of this method are well established. For the

single capillary technique, Harkins [51] gives:

y = \rhg(p — p') (7)

where y — surface tension (dyne cm-1

), r= radius

of capillary(cm), h = height of meniscus from immersed end of capillary(cm), g= acceleration of

gravity p= density of liquid measured (gem-3

) and p'

density of vapor (gem -3

). If a double

capillary assembly is used, the Sugden relation [52]

applies:

r-i*(P-p')4-s)" (8)

where y, g, p, p', carry the conventional signifi- cance and H is the vertical distance between the

lowest points of the menisci in the two vertical

tubes of radius ri and r2 (cm), and b\ and b> are the radii of curvature at these points (cm).

The derivations of eqs (7) and (8) assume a zero contact angle. This has been confirmed experimentally for water and some organic liquids in contact with glass by Richards and Carver [53];

the assumption has been carried over to molten

salt surface tension assemblies, apparently without

52
Table 2. Molten salt surface tension techniques: Theory and practice

Method Temperature range

(°C)

Surface tension

range (dyne cm -1

)

Maximum bubble pressure.. ambient- 1600 50-150

Capillary rise ambient- 200 10- 50

Plate 300- 900 50-150

Pin 350-1100 150-250

Pendant drop 100-2000 150-700

Cylinder 800-1400 50-150

Ring 650- 950 50-150

Sessile bubble 350- 500 10- 50

Equations

pr 2r 1 / r\ 2

3/i 6 \/(

Single cap. y = - rhg(p-p')

Double cap. y = - rHg(p-p')

[ff — ff

wtot— ^plate + 2y (/>+*)

y=—Aoff'd g

it; a0 =

1 + cuAt 2-77/0

Apply -7, dm, p to tables [56]

Cim Mg „

Mg

7

477/? f,ing

Use Bashforth and Adams tables

independent verification for such high temperature

systems.

3.5. Methods Based on the Shape of Static

Drops on Bubbles

The general procedure for this class of methods

is to form a liquid drop or a gas bubble in the liquid

studied under conditions such that it is not subject

to disturbance, and then to make certain measurements of its dimensions. These methods favor

the observations of long term changes in surface

tensions (i.e. , under conditions when slow time

effects are involved).

(a) Sessile Bubble Method*

This technique consists of forming a gas bubble

(inert gas) at the tip of a vertically mounted squareended tube immersed in the liquid which is contained in a spectrometer cuvette; microphoto-

*The application of the sessile drop method apparently has not been considered

lor fused salts in the open literature. However, the method has been found useful for some molten fluoride mixtures [93]. If the purities of the cover gas, the substrate, and

the fused salt are scrupulously maintained it is possible to obtain a precision better

than 3 percent. It is estimated that the absolute accuracy of this very straight-forward method may he as good as the precision.

graphic techniques are generally used to gain the

dimensions while the bubble is stationary. The

equatorial diameter and height of the bubble are thus gained (travelling microscope). The magnification factor can be checked readily by measuring

the diameter of the tube. Only one molten salt system, ZnCl2 [39] has been investigated by this

technique. The Bashforth and Adams Tables [62] were used to evaluate the surface tensions from the

dimensions of the bubbles. Because of difficulties

in measuring the pertinent dimensions the results are of low precision.

(b) Pendant Drop Method

In this technique, the salt is melted and contacted

with a rod of material that is inert to attack by the

melt. By withdrawing the rod a drop hangs pendant

on the end of the rod. Surface tension can be cal- culated from measurements of the absolute diameter of the pendant drop and a shape factor fixed

by a “selected” diameter, ds , defined as the diameter normal to the drop axis at a distance from the

base of the drop equal to the maximum diameter,

dm of the drop. The surface tension is related to the

liquid density, the absolute value of d,„, and the

ds

ratio -j- as given by Adamson [56] elsewhere.

Clm

53
The surface tensions of the oxide systems, A1 2 03 , B2O3, GeO-2, Si02 and P2O5 have been gained by

this method; the overall uncertainty is estimated to be about ± 7 percent.

3.6. Summary

Some of the preceding observations are presented

in a summary form in table 2. The ranges of surface

tensions and temperatures relative to the applicability of each method are illustrated in a bar graph

form in figure 2.

Figure 2. Surface tension range and temperature range for the various surface tension techniques.

A. Pendent drop: B. pin method; C. maximum bubble

pressure; D. Wilhelmy slide plate; E. ring method;

F. maximum pull on cylinder: G. sessile bubble; H. capillary rise. The vertical axis denotes the surface tension range in which the technique has been applied.

4. Treatment of Surface Tension Data

4.1. Statistical Analysis of Data

Linear and quadratic equations of surface tensiontemperature relationship were fitted to available

sets of experimental data by the method of least

squares. The calculations were made on the

digital computer facilities at Rensselaer Polytechnic Institute using double precision Fortran IV

language. The criterion for choosing a linear or quadratic equation of best fit for a set of surface

tension-temperature data is the standard deviation

computed from the residuals and is defined by:

S (>~7r)2 n-q

where ye = the experimental surface tension value

at each temperature, yc = the value calculated from

Ihe least squares equation at the same temperature

as ye , n = number of experimental data points, and

q = number of coefficients in the least squares equation (2 for linear and 3 for quadratic).

For most of the data, linear temperature-dependent equations proved the best fits; where there was

a large scatter of experimental points over a wide

temperature range, coupled with volatilizations

and/or with possible partial decomposition of the

melt, the quadratic equations were favored. If

5 -values of approximately the same magnitude were

found for both linear and quadratic equations, the

linear equation was chosen.

4.2. Selection of the Best Values

The data were classified into three general groups

as follows:

Group A— More than one set of experimental data

available

The surface tension investigations for each com- pound were assessed from the following viewpoints

to select the most thorough study: experimental

technique with emphasis on the preparation and

purity of the salt concerned; number of measurements; temperature range of the measurements and

chemical stability of the salt in this range: the standard error of estimate, 5, of the data. Where possible,

the uncertainty and precision of related molten salt results from each center were also taken into consideration. Departure graphs are used to illustrate

the data status for compounds in this group.

Group B — One set of experimental data reported

For about two-thirds of the compounds in this

group, the results are from one laboratory; a selection of "best value” is not feasible for these results.

Estimates of precision, 5, were obtained by least

squares regression analyses of the experimental

data, and uncertainties were estimated from a knowledge of the quantitative aspects of the experi54
mental procedures of the investigators. The remainder of the compounds were investigated in more

than one center and frequently by more than one

technique. Comparisons of values obtained from

different laboratories and/or by different experimental methods thus make possible a selection of

the best values for these salts. The final selection was always guided by details of the experimental

work as well.

Group C — No experimental data points reported

The results for compounds in this group (MgCL

and Ca(P03 )2 excepted) were reported from one

laboratory in the form of temperature-dependent

equations only. The selection of “best values” is not feasible for such systems; the surface tension

values in section 6 were gained from the equations;

the estimates of uncertainty and precision in the

temperature ranges within which the determinations were carried out are cited where possible.

As a subdivision within this group, salts were

included for which one or two experimental points

have been reported, e.g. UF<>, CuCl, HgCL, HgBr2 , A12 03 , PbO, FeO, and Cu2 S.

4.3. Estimation of Uncertainty

The departures of the results of individual in- vestigations from the recommended values were

used to firm up the estimates of uncertainty. Where

this was not feasible (e.g., salts in Group B and C) more qualitative factors such as experimental techniques and previous investigations of the authors were used as a guide for uncertainty estimates.

The precision of the data was an important consideration throughout. Such considerations lead

to values for the relative estimates of uncertainties

as low as ± 0.1 percent; however, it should be recognized that the absolute accuracy is not likely to be

better than ±2 percent. While it is generally ac- cepted that impurities have minor effects on the

surface tension of molten salts, the methods,

dependent on contact angle, trace impurities

(H2 O, FeO), may lead to significant errors, lor

FeO it has been estimated [90 1 than an error of

about 0.5 percent in composition affects the surface

tension values up to 2 percent.

For a comparison of the results from various

laboratories with the numerical values of this

compilation (sec. 6), the percent departure has been

calculated as follows:

Percent departure

compared value — tabulated valued

tabulated value

It should be noted that both the compared value

and the tabulated value are the numerical values

derived from the respective least squares equations.

Percent departure graphs are given where possible

to illustrate the results.

4.4. Preparation of the Tables

The surface tension values were computed for

each salt at 10 °C intervals from the corresponding

“best” equation for the same temperature range

for which the investigation was carried out. The

melting point of the salt, the “best” equation, the

precision estimate and the literature sources for

both the surface tension and melting point are given in each table (sec. 6). The underscored

literature reference indicates the source selected

for the best values.

5. Discussion

In this section the following information is given

for each compound; for the data used to gain the

best equation such details as experimental technique, number of data points, temperature range

are given; the precision, estimates of uncertainty,

and where possible, percent departure values and

graphs are also given; for many investigations the

preparation, purification, and stability of the

salt and other salient experimental features are discussed.

Lithium Fluoride, Rubidium Fluoride,

Cesium Fluoride, and Lithium Chloride

[Classification: Group A, see tables 3, 6, 7, and

10, pp. 78 and 79 for numerical values]

The surface tensions of these four halides have

been measured by Jaeger [46] and Ellis [37] (maximum bubble pressure method). The data of Ellis

for all four halides, LiF (34 points, 895 to 1095 °C),

RbF (38 points, 795 to 945 °C.), CsF (36 points, 775

to 920 °C), and LiCl (19 points, 645 to 865 °C) are recommended as the “best” values. Jaeger’s data

show departures of 7.1 to 6.8 percent for LiF, 1.9

percent to — 1.3 percent for RbF, 0.8 to 1.0 percent

for CsF, and 6.8 to 5.0 percent for LiCl in the same

temperature ranges, respectively. The departures

are illustrated in figure 3 (a-d), respectively.

Some of the experimental aspects of Ellis’ in- vestigation [37] are as follows: the precautions

outlined in section 3.2 for the maximum bubble

pressure technique were taken into consideration;

the surface tension assembly was in a dry box under

55
anhydrous conditions and nitrogen, the bubbling

gas, was passed through NaK before it entered

the capillary system.

900 1000 1100 1200 Temp. (°C)

The uncertainty estimates for these salts are: LiF, ±3.0 percent; RbF, ± 1.0 percent; CsF, ±1.0

percent, and LiCl, ±3.0 percent.

700 800 900 IOOO 1100 1200 Temp (°C)

600 700 800 900 1000 1100 Temp (°C)

Figure 3. Comparison of percent departures for the data for LiF, RbF, CsF, and LiCl.

a. LiF - Ellis (1961)1371

A Jaeger (1917) [46]

b. RbF - Ellis (1961) [37] O Jaeger (1917) [46]

c. CsF - Ellis (1961) [37] A Jaeger (1917) [46]

d. LiCl - Ellis (1961) [37]! O Jaeger (1917) [46]

Sodium Fluoride

[Classification: Group A; see table 4, p. 78

for numerical values]

The maximum bubble pressure technique has

been used by three groups, [32, 37, 46] to establish

the surface tension of molten NaF. The data of

Bloom and Burrows [32] are recommended as the

“best” values in the range 1000 to 1080 °C. Compared to the data of Bloom and Burrows, the results

of Ellis [37] and Jaeger [46] show considerable

departures (e.g., —13 percent and 9.8 percent,

respectively, at 1050 °C). This comparison is illus- trated in figure 4.

FIGURE 4. Comparison ofpercent departure of the data for NaF. — Bloom and Burrows (1960) [32

j

Q Jaeger (1917) [46] Ellis (1961) [37]

56
Some of the experimental aspects of the investigation of Bloom and Burrows [32] are as follows:

analytical reagent sodium fluoride (98% NaF)

was used; dry argon was used to form bubbles in

the melt.

The uncertainty is estimated to be no better than

± 8.0 percent.

Potassium Fluoride

[Classification: Group B: see table 5, p. 78

for numerical values]

The surface tension of KF has been studied by

Jaeger [46] (maximum bubble pressure technique).

The data (12 points, 912 to 1310 °C) can be ex- pressed by a quadratic equation (y = 176.2 — 0.108? — 0.333 X 10 -4

? 2

, 5 = 0.3 dyne cm -1

). The hygroscopic nature of KF and the wide temperature

range undoubtedly contribute, in part, to the

preference of a quadratic equation over a linear

equation.

Some of the experimental aspects of Jaeger’s

work are as follows: platinum capillaries of radii

0.

04935 to 0.05025 cm were used; nitrogen, the

bubbling gas, obtained by heating aqueous solutions

of NaNCL and NH4 C1, was purified by passing

respectively through alkaline-pyrogallol solution,

concentrated H2SO4 and P2O5; it was preheated to the melt temperature before passing through the

capillary system.

An accuracy estimate is not possible owing to insufficient information.

Rubidium Fluoride

(see under LiF, p. 55)

Cesium Fluoride

(see under LiF, p. 55)

Thorium Tetrafluoride and Uranium

Tetrafluoride

[Classification: Group C; see tables 8 and 9, p. 79

for numerical values]

The surface tensions of molten ThF4 and LF4 have been determined by Kirshenbaum and Cahill

[70] (maximum bubble pressure technique). About

25 experimental determinations were made over

the whole liquidus temperature range of each salt,

1.

e., ThF4 1110 °C (m.p.), 1680 °C (b.p.) and UF4 1036 °C (m.p.), 1450 °C (b.p.). Argon, the bubbling

gas, was passed through titanium flakes at 400 C C

to remove traces of nitrogen, oxygen, and water

vapor. The capillary tips were inspected after each

run and mechanically treated prior to use. The

main impurities in UF4 and ThF4 were UO2F2 and

Th02 respectively. X-ray diffraction patterns revealed that the concentration of Th02 in ThF4 melt was less than 1 wt percent. Analysis of UF4 melt at the end of the experiment indicated the presence

of 0.5 to 1.0 wt percent U02 F2 , while the starting

material contained 0.2 wt percent U02 F2 . The uncertainty estimates for both salts are ±3.0

percent.

Uranium Hexafluoride

[Classification: Group C; see table 10, p. 79 for

numerical values]

Two surface tension values have been reported

by Priest [50] : y = 1 7.66 ± 0.51 and 16.48 ± 0.06 dyne

cm-1at 65 °C and 72.5 °C, respectively. The

capillary rise method was used and all measure- ments were under vacuum. Pyrex glass (outgassed

and shown to be inert to attack by UFb) was used

for the experimental assembly. Uranium hexafluoride was purified by successive sublimations over anhydrous KF and distilled into the cell. The

radius of the capillary was obtained by calibration

with chloroform and benzene. An accuracy estimate

is difficult due to lack of information.

Cryolite

[Classification: Group C; see table 11, p. 79 for

numerical values]

The surface tension of molten Na3 AlF(> has been

determined by Bloom and Burrows [32] (maximum

bubble pressure technique). The tabulated values

for the range, 1000 to 1080 °C, were calculated

from the equation reported by the authors [32]

(7=262.0 — 0.128?, 5 = 1.9 dyne cm -1

). High-purity

natural cryolite (99.6% Na3 AlFf;) was used in this

investigation, the inert bubbling gas being dry

argon. An estimate of accuracy is difficult since

the experimental points were not reported and

experimental detail is minimal.

Lithium Chloride

(see under LiF, p. 55)

Sodium Chloride

[Classification: Group A; see table 13, p. 80 for

numerical values]

Three different techniques have been used to measure the surface tension of molten NaCl by

eight groups of investigators; the method of maximum bubble pressure was employed in six studies

[1, 4, 7, 13, 46, 60], the ring and Wilhelmy slide

plate techniques in the other two [10, 45]. The

results of Sokolova and Voskresenskaya [13] are recommended as the “best” values. The percent

departures of the values of the other investigators

from those of Sokolova are illustrated in figure 5.

57
Figure 5. Comparison of percent departures of the data for NaCl. — Sokolova and Voskresenskaya (1962) [13] O Bertozzi (1965) [45] A Semenchenko and Shikhobalova (1947) [4] Bloom. Davis and James ( 1960)[1 ] V Desyatnikov (1956) [60] + Lantratov (1961 )[7] # Jaeger (1917) [46] Some of the experimental aspects of Sokolova’s

investigation are as follows: NaCl was recrystallized

twice, dried at 250 °C and stored in a desiccator over sulfuric acid until required for use; the temperature gradient in the region of the specimen was

less than 0.5 deg cm-1 for a distance of 2.5 to 3 cm;

argon, used as the bubbling gas, was passed through

pyrogallol solution, dried with concentrated H2 SO4 and further with P2O5 supported on glass wool; a slow bubbling rate (one bubble per minute) was

used for the surface tension measurement.

The uncertainty is estimated to be ± 0.1 percent.

Potassium Chloride

[Classification: Group A; see table 14, p. 80

for numerical values]

Two different techniques have been used to measure the surface tension of molten KC1 by 10

groups; in nine [1, 4, 6 , 12, 29, 31, 40, 46, 60] the

maximum bubble pressure method was used, while

the Wilhelmy slide plate technique was used in

the remaining study [45]. The values of Dahl and

Duke [31] (5 = 0.4 dyne cm-1

) in the range 810 to 880 °C are recommended as the “best” values.

The departures of the values of other investigators

from those of Dahl and Duke are illustrated in

figure 6. Some of the experimental aspects of the investigation of Dahl and Duke are discussed on p. 61.

The accuracy is estimated to be ±0.5 percent.

Rubidium Chloride

[Classification: Group A; see table 14, p. 80

for numerical values]

Two different techniques have been used to measure the surface tension of molten RbCl by

1’lGURE 6. Comparison of percent departures of the data for KC.l. — Dahl and Duke (1957) [31a] ^ Semenchenko and Shikhobalova (1947) T4j Bertozzi (1965) [45]

'T Lehman (1959) [29J 9 Bloom. Davis, and James (1960) [1] O Peake and Bothwell (1954) [12] V Neithamer and Peake (1961) [6] Desyatnikov (1956) [60] A Jaeger (1917) [46]

[] Reding (1966) [40]

three groups; the maximum bubble pressure method

[4, 46], and the Wilhelmy slide plate method [45].

The values of Jaeger [46] are recommended as the

“best” values in the range 750 to 1150 °C. Compared

to the data of Jaeger, the results of Semenchenko

and Shikhobalova [4] and Bertozzi [45] show departures of 0.1 percent (900 to 1000 °C) and — 2.0 to — 0.6 percent (730 to 860 °C) respectively. Figure 7 illustrates this comparison.

FIGURE 7. Comparison of percent departures of the data for RbCl. — Jaeger (1917) [46[ O Semenchenko and Shikhobalova (1947) [4] V Bertozzi (1965) [45] Some of the experimental aspects of Jaeger's

work are discussed on p. 57. The uncertainty is estimated to be ± 0.1 percent.

Cesium Chloride

[Classification: Group A; see table 16, p. 81

for numerical values]

Two different techniques have been used for the

surface tension studies of molten CsCl by four

58
groups; in three [4, 29, 46] the maximum bubble

pressure was used, while the Wilhelmy slide plate

method was used in the other [45]. The values of

Jaeger [46J are recommended as the “best” values

in the range 663 to 1083 °C. Compared to the data

of Jaeger, the results of Bertozzi [45], Semenchenko

and Shikhobalova [4] and Lehman [29] show departures of— 0.2 percent (700 to 800 °C), —0.2 to 0.4

percent (900 to 1080 °C), and —2.9 to — 1.0 percent

(750 to 880 °C) respectively; this is illustrated in figure 8.

FIGURE 8. Comparison of percent departures of the data for CsCl. — Jaeger (1917) [46] O Semenchenko and Shikhobalova (1947) [4] A Bertozzi (1965) [45] Lehmen (1959) [29] Some of the experimental aspects of Jaeger’s

[46] work are discussed on p. 57. The uncertainty

is estimated to be +0.2 percent.

Cuprous Chloride and Cuprous Sulfide

[Classification: Group C; see table 17, p. 81

for numerical values]

One experimental point for each compound,

reported by Boni and Derge [92], appear to be the

only values established to date. The melts were

contained in alumina crucibles and the surface

tensions were measured by the maximum bubble

pressure technique, with argon as the bubbling gas. The information is insufficient for an accuracy

estimate.

Silver Chloride, Silver Bromide, and

Silver Iodide*

[Classification: Group C; see tables 18 and 26,

pp. 81 and 83 for numerical values]

The surface tension of molten AgCl and AgBr

have been determined by Boardman, Palmer, and

Heymann [14] (maximum bubble pressure tech-

^Silver iodide was also studied by the same authors [14] over the temperature range

560 to 620 °C, but no values were reported. Above 620 °C, Agl decomposes and repro- ducible surface tension results are not possible.

nique). No thermal decomposition was observed in the temperature ranges investigated, i.e., AgCl

(460 to 700 °C) and AgBr (460 to 620 °C).

The capillaries were drawn from British-ThomsonHouston C46 glass tubing and were calibrated with

tap water. Nitrogen was used as bubbling gas;

details of purification were not given. Contact of the

capillary tip with the melt surface was determined

visually. Mechanical checks and recalibration of the

capillaries were done after each experiment.

The uncertainty of the data for both salts is esti- mated to be ± 1.0 percent.

Magnesium Chloride

[Classification: Group C; see table 19, p. 81 for

numerical values]

Two different techniques have been used to measure the surface tension of molten MgCL; the maximum bubble pressure method [40, 60] and the ring

method [10]. The values of Desyatnikov [60] are recommended as the “best” values in the temperature range of 720 to 930 °C. The results of Barzakovskii [10] and Reding [40] showed departures of ±0.1

percent and 8.5 to 7.5 percent respectively in the

same temperature range; these are illustrated in

figure 9.

Figure 9. Comparison of percent departures of the data for MgCfi. — Desyatnikov (1956) [60] A Reding (1966) [40] # Barzakovskii (1940) [10] Some details of the Desyatnikov investigation are

as follows: anhydrous MgCL was melted under a stream of dry hydrogen chloride over a period of

6 to 8 hr to prevent hydrolysis; analysis for SCR and

Fe indicated that these constituents did not exceed

0.005 percent, while the MgO content was found to be about 0.2 to 0.4 percent; CCL was used as the

bubbling gas and was bubbled through the melt for

20 to 30 min prior to the surface tension measurements; due cognizance of the precautions outlined

in section 3.2 was taken; the capillary tips were

refinished before each experiment, and the bubbling

rate was 2 to 3 bubbles per minute; measurements

335-493 0-69 —5 59
at each temperature were carried out consecutively with three capillaries, each of a different

diameter.

The uncertainty is estimated to be ±0.8 percent.

Calcium Chloride

[Classification: Group A; see table 20, p. 82 for

numerical values]

The surface tension of molten CaCl2 has been

determined by three groups [7, 29, 37] (maximum

bubble pressure method). The values of Ellis [37]

in the range 840 to 920 °C are recommended as the

“best” values. The departures of the values of the

other investigators from those of Ellis are: Lantratov

[7], — 0.5 to + 0.5 percent in the range 720 to 870 °C

and Lehman [29], 2.0 to 5.5 percent in the range

796 to 914 °C. These are shown in figure 10.

FIGURE 10. Comparison of percent departures of the data for CaCl2 . - Ellis (1961) [37) O Lehman (1959) [29J Lantratov (1961) [7|

Some of the experimental aspects of Ellis’ in- vestigation are discussed on p. 55. CaCl2 was

prepared by the action of HC1 on CaC03 . The

crystallized product was dried under vacuum (0.3

mm Hg) at about 300 °C over a period of 48 hr. The

product was then transferred to a Vycor flask*

attached to a high vacuum system, (25 /u.m or better)

and fused. The temperature was increased gradually over a period of 3 to 4 days, after which the salt was kept molten for several hours. The vacuum was

broken with dry N2 , followed by bubbling the melt

with anhydrous HC1. The salt was then cooled in an atmosphere of HC1, the sample was transferred

to a mason jar for storage (Cl, 35.69% by analysis;

35.82% theoretical.)

The uncertainty is estimated to be ±0.5 percent.

’Certain commercial products and instruments are identified in order to specify adequately the experimental procedure. In no case does such identification imply recommendation or endorsement by the National Bureau of Standards, nor does it imply that the product or equipment identified are necessarily the best available

for the purpose.

Strontium Chloride

(see under CaL, p. 65)

Barium Chloride

[Classification: GroupA; see table 22, p. 82 for

numerical values]

The surface tension of molten BaCL has been

determined by two groups [12, 13] (maximum bubble

pressure technique). The results of Peake and

Bothwell [12] (8 points, 981-1041 CC) are recom- mended as the “best” values. Compared to the

values of Peake and Bothwell, the data of Sokolova

and Voskresenskaya [13] show departures of 2.4

to 3.2 percent in the same temperature range; this

comparison is illustrated in figure 11.

960 980 1000 1020 1040 Temp. (°C)

Figure 11. Comparison of percent departures of the data for BaCl2 . — Peake and Bothwell (1954) [12] Q Sokolova and Voskresenskaya (1962) [13) Some of the experimental details of the work of

Peake and Bothwell are discussed on p. 73. The

uncertainty is estimated to be ±1.0 percent.

Zinc Chloride and Zinc Bromide

[Classification: Group C; see tables 23 and 40, pp. 82 and 87 respectively for numerical values]

The surface tensions of these two zinc halides

have been determined by Ellis [39] using the sessile

bubble technique. Results showed that the temperature coefficients of surface tension for both of

these salts were not constant over the ranges of

temperature of investigation (ZnCL, 300 to 720 °C

and ZnBr2 , 500 to 670 °C).

Some of the experimental aspects of Ellis’ in- vestigation are as follows: N.F. grade zinc halides were dehydrated by heating gently under vacuum

up to their melting points, sparging the melt with

the corresponding anhydrous hydrogen halide up to 700 °C and then purging the melt with purified and

dried argon or helium.

The uncertainties are estimated to be ±3.0 per- cent (in the range 300 to 550 °C for ZnCl2 and 500

to 600 °C for ZnBr2 ) and ±1.5 percent (in the range

550 to 700 °C for ZnCl2 and 600 to 700 °C for ZnBr2 ).

60
Cadmium Chloride, Cadmium Bromide,

Calcium Bromide, and Barium Iodide

[Classification: Group B; see tables 24, 41. 35,

and 49, pp. 83, 85. 87, and 89 respectively for

numerical values]

The surface tensions of these four Group II metal

halides have been determined by Ellis [35, 37]

(maximum bubble pressure technique). The data

for CdCE (14 points, 580 to 921 °C) and CdBr2 (38

points, 635 to 775 °C) are better represented by

quadratic equations (5 = 0.3 dyne cm-1 and 5= 1.0

dyne cm-1 respectively), while those for CaBr2 (3 points, 774 to 809 °C) and Bal2 (9 points, 826 to 958 °C) are represented by linear equations (5 = 0.3

dyne cm-1 and 5=0.4 dyne cm-1 respectively).

The precautions outlined in section 3.2 for the

maximum bubble pressure technique were taken

into consideration. The surface tension assembly was in a dry box under anhydrous conditions and

nitrogen, the bubbling gas, was passed through

NaK before it entered the capillary system.

The anhydrous salts were prepared and purified

as follows: CdCl2 — Reagent-grade CdCL was vac- uum dried at 200° C for 2 days; CdBr2 — Reagentgrade CdBr2 was vacuum dried at 200 °C for 2

days; CaBr2 — CaBr2

• nTGO was first predried

under vacuum (0.3 mm Hg) at 300 °C; it was then

transferred to a Vycor flask attached to a high

vacuum system (25 fjtm or better) and fused; the

temperature was increased gradually over a period

of 3 to 4 days, after which the salt was kept molten

for several hours; the vacuum was broken in dry

nitrogen atmosphere followed by bubbling the melt

for several hours with anhydrous HBr; the salt was

then cooled in an atmosphere of HBr and transferred

to a mason jar for storage (Br, 79.79% by analysis;

79.95%, theoretical); Bal2 -Barium Iodide (obtained

from John Harrison Laboratory, University of

Pennsylvania) was used without further purification.

The uncertainty of the surface tension data for

the above salts is estimated to be ±1.0 percent.

Stannous Chloride

[Classification: Group A; see table 25, p. 83 for

numerical values]

The surface tension of molten SnCL has been

measured by Jaeger [46] and Ellis [35] (maximum

bubble pressure method). The data of Ellis (8 points,

280 to 480 °C) are recommended as the “best"

values. Comparison of percentage departure of

Jaeger’s results is illustrated in figure 12. Some of the experimental aspects of Ellis’ investigation are discussed on p. 55. SnCU was

prepared by fusing commercial anhydrous stannous

chloride under vacuum, sparging with anhydrous

HC1 and finally filtering under vacuum through a sintered Pyrex disk.

The uncertainty is estimated to be ± 1.0 percent.

300 400 500 Temp (°C)

FIGURE 12. Comparison of percent departures of the data for SnCl2 . - Ellis (1958) [35] O Jaeger (1917) |"46]

Mercuric Chloride and Mercuric Bromide

[Classification: Group C; see table 26, p. 83 for

numerical values]

The surface tensions of molten HgCl2 and HgBr2 have been determined by Prideaux and Jarratt [59]

(maximum bubble pressure method). Very few

experimental details were given by the investigators.

Mercuric chloride and mercuric bromide exhibit narrow liquidus temperature ranges [69] (277 to 304 °C and 241 to 319 °C respectively).

An accuracy estimate is not possible owing to insufficient information.

Lead Chloride

[Classification: Group B; see table 27, p. 83 for

numerical values]

Two different techniques have been used to measure the surface tension of molten PbCL by

three groups; the maximum bubble pressure method

[1, 31] and the ring method [10]. The values of Dahl

and Duke [31] in the temperature range 520 to 580 °C

are recommended as the “best” values. Compared

to the data of Dahl and Duke, the results of Bloom,

Davis, and James [1] and Barzakovskii [10] show

departures of ±0.3 percent and 5 to 10 percent

respectively. The volatility of the melt partially

accounts for the high percent departure of the -values

by the ring method. Comparison of percent departure of the data of Bloom et al. is illustrated in figure

13. Some of the experimental aspects of the investigation of Dahl and Duke [31] are as follows: The

precautions outlined in section 3.2 for the maximum

bubble pressure technique were taken into consideration. PbCL (Baker and Adamson) was heated

to a temperature just above its melting point (498 °C),

cooled, powdered, and stored in a drying oven at 110 °C until used. The system was under an atmosphere of helium during surface tension measurement.

The uncertainty is estimated to be ±1.0 percent.

61
1.0

S5 -0.5 -

_l 0 l —j- —J 500 550 600

Temp, (°C)

FIGURE 13. Comparison of percent departures of the data for PbCk

— Dahl and Duke (1958) [31] O Bloom. Davis and James (1960) [1 ] Aluminum Chloride

[Classification: Group B; see table 28, p. 84 for

numerical values]

The surface tension of molten A1C13 has been

determined by Nisel’son and Sokolova [61] (200 to 320 °C, capillary rise technique). The anhydrous

salt was prepared by doubly distilling analytical

reagent grade AlCfi in evacuated glass ampules

with a few aluminum turnings to reduce any impurity of iron to the divalent form (less volatile).

Capillaries made of borosilicate glass (readily

wetted by liquid A1C13 ) were used.

An estimate of accuracy is not possible owing to insufficient information.

Gallium Trichloride

[Classification: Group A; see table 29, p. 84 for

numerical values]

The surface tension of molten GaCl3 has been

determined by two groups [44, 61] (capillary rise

technique). The data of Greenwood and Wade [44]

(15 points, 80 to 140 °C) are recommended as the

“best” values. The results of Nisel’son and Sokolova

[61] show departure of — 4.8 to— 5.7 percent in the

same temperature range. This comparison is illus- trated in figure 14. The uncertainty for the surface tension values is estimated to be ±3.0 percent.

Gallium Trichloride Monopiperidine, Gallium

Trichloride Dipiperidine, and Gallium Trichloride Pyridine Complex

[Classification: Group C; see table 30, p. 84 for

numerical values]

The surface tension for these organic complex

compounds of GaCl3 were investigated by Greenwood and Wade [42, 43] (120 to 160 °C; doublecapillary rise method). The thermal stability for

this series of compounds was confirmed as part

of this investigation through the related physical

6 -

4

FIGURE 14. Comparison of percent departures of the data for GaCk

— Greenwood and Wade (1957) [44] O Niselson and Sokolova (1965) [61].

property measurements, e.g., conductivity, vis- cosity, density, and vapor pressure. Although the

experimental details for the surface tension meas- urements were insufficient to warrant an accuracy

estimate, the data appear to be of good quality.

Bismuth Trichloride and Bismuth Tribromide

[Classification: Group B; see tables 31 and 42, pp.

84 and 87 respectively]

The surface tensions of molten BiCl3 and BiBr3 have been determined by Jaeger [46] (maximum

bubble pressure technique). The data for both

BiCl3 (5 points, 271 to 382 °C) and BiBr3 (9 points,

250 to 442 °C) are better represented by quadratic

equations (5 = 0.1 dyne cm -1 and 5 = 0.1 dyne cm -1 respectively).

The experimental technique and the uncertainty

of the data of Jaeger are discussed on p. 73.

Bismuth trichloride and bismuth tribromide are thermally stable up to their boiling points 441 °C

and 461 °C respectively [69],

Sodium Bromide

[Classification: Group A; see table 32, p. 85 for

numerical values]

Two different techniques have been used to measure the surface tension of molten NaBr by

four groups; the maximum bubble pressure method

[1, 13, 46] and the Wilhelmy slide plate method

[45]. The results of Sokolova and Voskresenskaya

[13] (10 points, 750 to 800 °C) are recommended as the “best” values. The values of Bloom, Davis,

and James [1], Bertozzi [45], and Jaeger [46] show

departures of —5 to —3 percent (750 to 850 °C), — 0.5 to 0.5 percent (750 to 850 °C) and 2.0 to 2.5

percent (700 to 800 °C) respectively. These are

illustrated in figure 15.

62
FIGURE 15. Comparison of percent departures of the data for NaBr. — Sokolova and Voskresenskaya (1962) [1 3

]

V Jaeger (1917) [46] O Bertozzi ( 1965) [45] Bloom, Davis and James (1960) [1] Some of the experimental aspects of the investigation of Sokolova and Voskresenskaya are discussed

on p. 58. The uncertainty is estimated to be ±0.5

percent.

Potassium Bromide

[Classification: Group A; see table 33, p. 85 for

numerical values]

Two different experimental techniques have

been used to measure the surface tension of

molten KBr by four groups; the maximum bubble

pressure method [1, 36, 46] and the Wilhelmy slide

plate method [45]. The results of Bloom, Davis,

and James [1| are recommended as the “best”

values in the range 750 to 950 °C. The departures

of the values of other investigators are: Ellis [36],

1.8 to 3.2 percent (803 to 972 °C); Bertozzi [45],

2.9 to 3.0 percent (740 to 850 °C) and Jaeger [46], — 1.0 to —0.8 percent (775 to 920 °C). These departures are illustrated in figure 16. Some of the experimental aspects of the investigation of Bloom et al. are as follows: analytical

reagent grade KBr was oven dried before use; dry

nitrogen was used to bubble through the melt; the

precautions outlined in section 3.2 for the maximum

bubble pressure were taken into consideration.

The uncertainty is estimated to be ± 1.0 percent.

Rubidium Bromide and Cesium Bromide

[Classification: Group B; see tables 34 and 35,

p. 85 for numerical values]

Two different techniques have been used to measure the surface tension of molten RbBr and CsBr

by two groups; the Wilhelmy slide plate method [45]

and the maximum bubble pressure method [46].

The results of Bertozzi [45] are recommended as the

700 800 900 1000 Temp (°C)

FIGURE 16. Comparison of percent departures of the data for KBr. — Bloom, Davis and James (1960) [1] V Bertozzi (1965) [45] Jaeger (1917) [46] Q Ellis (1959) [36

1

“best” values for both salts. Jaeger’s results show

departures of 2.5 to 3.0 percent in the range 720

to 830 °C for RbBr and — 0.5 to — 1.0 percent in the

range 666 to 750 °C for CsBr. The departures are shown in figure 17 (a, b). The uncertainties for these two salts are esti- mated to be ±0.6 percent.

700 800 900 1000 IIOO Temp (°C)

FIGURE 17. Comparison of percent departures of the data for RbBr and CsBr.

a. RbBr — Bertozzi (1965) [45] O Jaeger (1917) [46]

b. CsBr — Bertozzi (1965) [45] A Jaeger (1917) [46

1

63
Calcium Bromide Some of the experimental aspects of Ellis' in- vestigation are discussed on p. 55. The uncer-

(see under CdCl>, p. 61) tainty for this salt is estimated to be ±0.2 percent.

Strontium Bromide

(see under Cal2 , p. 65)

Barium Bromide

(see under Cal2 , p. 65)

Zinc Bromide

(see under ZnCl2 , p. 60)

Cadmium Bromide

(see under CdCl2 , p. 61)

Mercuric Bromide

(see under HgCL, p. 61)

Bismuth Bromide

(see under BiCl;! , p. 62)

Sodium Iodide

[Classification: Group A; see table 43, p. 87 for

numerical values]

The maximum bubble pressure technique has

been used by three groups [1, 37, 46] to measure

the surface tension of molten Nal. The results of

Ellis [37] (28 points, 755 to 885 °C) are recommended

as the ‘'best” values. The departures of the values

of Bloom. Davis, and James [1] and Jaeger [46] are — 4.5 percent and —0.5 to 4.0 percent respectively

in the range 760 to 820 °C. These are illustrated in

figure 18.

Figure 18 . Comparison of percent departures of the data for

Nal. - Ellis (1961) [37] Jaeger (1917) [46] G Bloom. Davis and James (1960) [1]

Potassium Iodide

[Classification: Group B; see table 44, p. 88 for

numerical values]

The surface tension of molten KI has been

measured by Jaeger [46] and Bloom, Davis, and

James [1] (maximum bubble pressure method).

The values of Bloom et al. in the range 700 to 900

°C are recommended as the “best” values (5 = 0.2

dyne cm-1

). The percent departure of Jaeger's

results from those of Bloom, Davis, and James is illustrated in figure 19. Some of the experimental details of the investigation of Bloom et al. are as follows: analytical

reagent grade KI was oven dried before use; dry

nitrogen was used to bubble through the melt;

the precautions outlined in section 3.2 for the

maximum bubble pressure were taken into consideration.

The uncertainty is estimated to be ±0.5 percent.

Rubidium Iodide and Cesium Iodide

[ Classification: Group B; see tables 45 and 46.

p. 88 for numerical values]

The surface tensions of molten Rbl and Csl have

been determined by Jaeger [46] (maximum bubble

pressure technique). The data for both Rbl (8 points.

673 to 1016 °C) and Csl (8 points, 653 to 1030 °C)

are better represented by quadratic equations

(5 = 0.1 dyne cm -1 and 5 = 0.2 dyne cm -1 respectively).

Some of the experimental aspects of Jaeger's

investigation are discussed on p. 57. An accuracy

estimate is not possible owing to limited information.

700 800

Temp (°C)

FIGURE 19. Comparison of percent departure of the data for KI. — Bloom. Davis and James (1960) [1|

G Jaeger (1917) [46

64
Calcium Iodide, Strontium Chloride, Strontium Bromide, Strontium Iodide, and

Barium Bromide

[Classification: Group B; see tables 47, 21, 38, 48,

and 49, pp. 89, 82, 86, 89, and 89 respectively for

numerical values]

The surface tensions of these five alkaline earthmetal halides have been measured by Ellis [34]

(maximum bubble pressure technique).

The precautions outlined in section 3.2 for the

maximum bubble pressure technique were taken

into consideration. The surface tension assembly was in a vacuum type dry box. The compounds were

prepared by thermal dehydration of the corresponding reagent grade hydrates under vacuum. A pres- sure of 0.3 mm mercury was maintained and

temperatures up to 300 °C were used. The drying

periods were 48 to 72 hr during which time heat was

applied gradually. Both Cal2

• «H2 0 and SrBr2 -6H2 0

were mixed with an excess of the corresponding

ammonium halide and ball milled prior to vacuum

drying. Strontium iodide was synthesized by the

reaction of HI and SrC03 and dehydrating the crystallized product.

The uncertainty of the surface tension data for

these five salts is estimated to be± 1.0 percent.

Strontium Iodide

(see under Cal2 , p. 65)

Barium Iodide

(see under CdCl2 , p. 61)

Boron Trioxide

[Classification: Group B; see table 50, p. 90 for

numerical values]

Two different techniques have been used to measure the surface tension of molten B2 03 : the maximum pull on cylinder technique [33] and the pendant

drop technique [30]. The results of Shartsis and

Canga [33] are recommended as the “best” values;

the precision for the data is estimated to be 5 = 0.04

dyne cm-1. Both investigations showed a positive

temperature coefficient. Fajans [94] has discussed

some anomolous temperature coefficients for sur- face tension and other physical properties for B2 03 . The departure of Kingery’s values from those of

Shartsis and Canga varies from —5 percent to +5

percent in the range 800 to 1200 °C. This is illus- trated in figure 20.

Some of the experimental features of Shartsis and

Canga are as follows: the oxide was prepared by

thermal dehydration of boric acid; the temperature was controlled to ±5 °C during the measurement; a

sensitive optical lever was incorporated into the

analytical balance to increase the sensitivity of

FIGURE 20. Comparison of percent departures of the data for B2 03 . — Shartsis and Canga (1949) [33] A Kingery (1959) [30]

measuring the maximum pull exerted on the cylinder

(Pt — 20% Rh); measurements were taken at 100 °C

intervals.

The uncertainty is estimated to be ±4.0 percent.

Aluminum Oxide, Silicon Dioxide, and

Germanium Dioxide

[Classification: Group C; see tables 49, 50, and 51,

pp. 89 and 90 for numerical values]

The surface tensions of molten Al2 0.3, Si02 and

Ge02 have been measured by Kingery [30] (pendant

drop technique). In the case of A12 03 , only one

determination was made at 2050 ±15 °C (y=690

dyne cm-1

). For Si02 , and Ge02 , the temperature

coefficients of surface tension were determined;

these values are positive, showing an unusual temperature dependence of the surface tension property

in these single-component liquids.

Some of the experimental details of Kingery’s

investigation are as follows: samples of A1203 were formed by coating the tip of a molybdenum rod with

a suspension of the melt and melting in an atmosphere of purified helium; with Si02 and Ge02 , samples were formed by dipping a platinum rod in the

corresponding oxide melt (in a platinum crucible)

to gather a satisfactory gob; all materials were of

analytical reagent-grade purity and were used without further purification; owing to clouding of the

furnace windows, a significant error was introduced

in the temperature measurement.

The uncertainty for the surface tension values is estimated to be no better than ± 7.0 percent.

Lead Oxide

[Classification: Group C; see table 51, p. 90 for

numerical values]

The surface tension of PbO has been measured

by Shartsis, Spinner, and Smock [91] (maximum

pull on cylinder). The two values reported (132.0

65
dyne cm-1 at 900 °C and 134.8 dyne cm-1 at 1000 °C)

indicate a positive temperature coefficient in this

range of temperature.

Some of the experimental aspects of the investigation of Shartsis, Spinner, and Smock [91] are discussed on p. 65. An accuracy estimate is not possible

owing to insufficient information.

Phosphorous Trioxide

[Classification: Group B; see table 54, p. 91 for

numerical values]

The surface tensions for this compound have

been measured by Schenck, Mihr, and Banthien

[5]. The data (4 points, 30 to 110 °C) have been used

to generate a linear equation and the precision is 5 = ± 0.2 dyne cm-1

. An accuracy estimate is not possible owing to insufficient information.

Phosphorus Pentoxide

[Classification: Group C; see table 55, p. 91 for

numerical values]

Surface tension data for “liquid P2O5” in the

temperature range of 100 to 300 °C, have been re- ported by Kingery [30]. Comparison with the melting

point [69] for anhydrous P2O5, indicates that the

samples used by Kingery were not one-component

systems, but consisted possibly of a mixture of

phosphorus oxides and/or were not anhydrous P2O5.

Ferrous Oxide

[Classification: Group C; see table 51, p. 90 for

numerical values]

The surface tension of FeO has been measured

by Kozakevitch [90] (maximum pull on cylinder

technique). The data (5 points) cover a very narrow

temperature range (1415 to 1423 °C); also the Fe2 03

impurity in the oxide was as much as 5 wt percent.

It was estimated by the author that an error of 0.5

percent in composition may result in an error of 1 to 2 percent in the surface tension value. No attempt

to generate an equation is made; instead a mean

value of 585 dyne cm-1

is reported. This value is in reasonable agreement with the one reported

elsewhere [87].

Cuprous Sulfide

(see under CuCl, p. 59)

Thallous Sulfide

[Classification: Group C; see table 56, p. 91 for

numerical values]

The surface tension of TLS has been determined

by Lazarev and Abdusalyamova [85] (maximum

bubble pressure technique) in the range 500 to 700 °C. The experimental data (5 points) give the

following linear equation: 7= 231.4 — 0.0356?

(5 = ±0.4 dyne cm -1). An accuracy estimate is not possible owing to insufficient information.

Lithium Metaborate, Sodium Metaborate,

and Potassium Metaborate

[Classification: Group B; see tables 57, 58, and 59

p. 92 for numerical values]

The surface tensions of these three high melting

salts have been determined by Jaeger [46] (maximum bubble pressure technique). The experimental

data of Jaeger for LiBCL (14 points, 880 to 1520 °C),

NaBC>2 (10 points, 1015 to 1441 °C) and KB02 (4 points, 992 to 1142 °C) have been used to generate

the corresponding least squares equations.

The experimental aspects and the accuracy

estimates of Jaeger’s investigation are discussed on p. 73. Decomposition of LiBCL into LbO at 1200 °C was observed by the author.

Lithium Carbonate

[Classification: Group B; see table 60, p. 92 for

numerical values]

Two different methods have been used to measure

the surface tension of Li2 C03 by two groups; the

pin detachment method [49] and the maximum

bubble pressure method [76]. The values of Janz

and Lorenz [49] are recommended as the “best"

values in the range 750 to 850 °C. The results of

Moiseev and Stepanov [76] show departures of

0.3 to 0.6 in the same temperature range. The

departure is illustrated in figure 21.

Some of the experimental details of the investigation of Janz and Lorenz are as follows: Li2 C03,

reagent grade quality, was dried to constant weight

under an atmosphere of CO2 at 600 °C and stored

in a desiccator over P2O5 until required; surface

750 800 850 900

Temp. (°C)

Figure 21. Comparison of percent departures of the data for Li,CO:i . — Janz and Lorenz (1961) [49|

O Moiseev and Stepanov (1964) [76

66
tension measurements were made in an atmosphere

of CO2 at pressures in large excess to the dissociation partial pressure of the carbonate; since dissociation to oxide would lead to irreproducibility, the

measurements were made in thermal cycles at temperatures randomly selected, first higher,

then lower, then higher and so on, to detect possible

changes in the values of the surface tension.

The uncertainty is estimated to be ±0.3 percent

or better.

Sodium Carbonate and Potassium Carbonate

[Classification: Group B; see tables 61 and 62 p. 93

for numerical values]

The surface tensions of these two molten car- bonates have been determined by Janz and Lorenz

[49] (pin detachment method). The linear equation

expresses the data (10 points, 870 to 1010 & C) for

Na2 CO,3 with a precision, 5 = 0.1 dyne cm -1

, and

the quadratic equation expresses the data for

K2CO3 (14 points, 910 to 1010 °C) with precision,

5 = 0.2 dyne cm -1

. Some of the experimental aspects of the investigation of Janz and Lorenz are discussed on p. 66.

The uncertainty is estimated to be ±0.3 percent

or better.

Lithium Nitrate

[Classification: Group B; see table 63, p. 93 for

numerical values]

Two different techniques have been used to measure the surface tension of molten LiN03 by

three groups; the maximum bubble pressure method

[19, 46] and the Wilhelmy slide plate technique

[26]. The values of Bertozzi and Sternheim [26] are recommended as the “best” values in the temperature range 300 to 500 °C. The results of Jaeger [46]

and Addison and Coldrey [19] show departures of

1.5 to 0.3 percent and —0.3 to + 0.2 percent respectively in the same temperature range; these departures are shown in figure 22.

FIGURE 22. Comparison of percent departures of the data for UNO3. — Bertozzi and Sternheim (1946) [26] O Jaeger (1917) [46] Addison and Coldrey (1961) [19]

Some of the experimental details of the investigation of Bertozzi and Sternheim are as follows: a platinum plate (edge length 15 mm and thickness

0.1 mm) was used. The temperature was measured

a few mm above the surface of the melt and was

accurate to ± 1 °C. B. D. H. salts of analytical purity were dried and used without further purification.

The uncertainty is estimated to be ±0.5 percent.

Sodium Nitrate

[Classification: Group A; see table 64, p. 93 for

numerical values]

Two different techniques have been used to measure the surface tension of molten NaN03 by six

groups; the maximum bubble pressure method

[1, 18, 19, 41, 46], and the Wilhelmy slide plate

method [26] . The results of Dahl and Duke [18]

(22 points, 320 to 600 °C) are recommended as the

“best” values. The departure of the values of other

investigators are: Bloom, Davis, and James [1],—

2

to 1 percent; Addison and Coldrey [19], —2 to — 1 percent; Semenchenko and Shikhobalova [41], — 0.5

to 2.5 percent; Bertozzi and Sternheim [26], —0.6

to —0.4 percent and Jaeger [46], 0.9 to 1.3 percent.

The percent departures are shown in figure 23.

The experimental aspects of the investigation of

Dahl and Duke [18] are discussed on p. 61. The

uncertainty is estimated to to ±0.5 percent.

Potassium Nitrate

[Classification: Group A; see table 65, p. 94 for

numerical values]

Three different techniques have been used to measure the surface tension of molten KNO3 by six

groups; the maximum bubble pressure method

[1, 18, 19, 46], the Wilhelmy slide plate technique

[26] and the pin method [48]. The values of Janz and

Figure 23 Comparison of percent departure of the data for NaN03 . — Dahl and Duke (1958) [18] O Semenchenko and Shikhobalova (1947) [41] V Jaeger (1917) [46]

[] Bloom, Davis and James (1960) [1] A Bertozzi and Sternheim (1964) [26] Addison and Coldrey (1961) [1 9

1

67
Lorenz [48] are recommended as the “best” values

(5 = 0.1 dyne cm -1

) in the range 345 to 465 °C. The

departures of the values of the other investigators

from those of Janz and Lorenz are: Bloom, Davis,

and James [1], — 1.6 to — 0.3 percent; Addison and

Coldrey [19], 0.7 to —0.5 percent; Bertozzi and

Sternheim [26], 1.1 to 0.5 percent; Dahl and Duke

[18], 2 percent and Jaeger [46], 2.2 percent. The

percent departures are shown in figure 24.

The experimental aspects of the investigation of

Janz and Lorenz [48] are discussed on p. 66. The

uncertainty is estimated to be ±0.5 percent.

Rubidium Nitrate

[Classification: Group B; see table 66, p. 94 for

numerical values]

Two different techniques have been used to measure the surface tension of molten RbN03 by two

groups; the maximum bubble pressure method

[46] and the Wilhelmy slide plate technique [26]. The

values of Bertozzi and Sternheim [26] are recom- mended as the “best” values in the range 330 to 600 °C. The percent departure of Jaeger’s values

from those of Bertozzi and Sternheim varies from — 0.3 to —3.8 in the same temperature range; this is shown in figure 25.

Some of the experimental details of the investigation of Bertozzi and Sternheim are discussed on

p. 67. The uncertainty for this salt is estimated to be ± 0.5 percent.

Cesium Nitrate

[Classification: Group B; see table 67, p. 94 for

numerical values]

Two different techniques have been used to measure the surface tension of molten CsN03 by

three groups; the maximum bubble pressure

FIGURE 24. Comparison of percent departures of the data for KNO:! . — Janz and Lorenz (1960) [48] O Jaeger (1917) [46] T Dahl and Duke (1958) [18] A Bertozzi and Sternheim (1964) [26] + Addison and Coldrey (1961) [19] • Bloom, Davis and James (1960) [1]

Figure 25. Comparison of the percent departures of the datafor RbN03. — Bertozzi and Sternheim (1964) [26] Q Jaeger (1917) [46]

method [19, 46], and the Wilhelmy slide plate technique [26]. The values of Bertozzi and Sternheim

[26] are recommended as the “best” values in the

range 420 to 600 °C. Compared to the results of

Bertozzi and Sternheim the values of Addison and

Coldrey [19] show departures of 1.0 to 2.5 percent

in this range, while those of Jaeger [46], show departures of 1.5 to —1.0 percent for the same range.

The departures are illustrated in figure 26.

Some of the experimental details of the investigation of Bertozzi and Sternheim [26] are discussed on p. 67. The uncertainty for this salt is estimated

to be ±0.5 percent.

Silver Nitrate

[Classification: Group B; see table 68, p. 94 for

numerical values]

Two different techniques have been used to measure the surface tension of molten AgN03 by

four groups; the maximum bubble pressure method

[1, 18, 19] and the Wilhelmy slide plate method

[26]. The values of Dahl and Duke [18] are recom- mended as the “best” values in the temperature

range 222 to 352 °C. Compared to the data of Dahl

Figure 26. Comparison of percent departures of the data for CsN03 . — Bertozzi and Sternheim (1964) [26] O Addison and Coldrey (1961) [19] Jaeger (1917) [46]

68
and Duke, the values of Bloom, Davis, and James

[1], Addison and Coldrey [19] and Bertozzi and

Sternheim [26] show departures of —0.9 to 0.05

percent, 1.4 to —0.2 percent and 0.1 to —0.4 percent respectively in the same temperature range.

These departures are illustrated in figure 27.

The experimental aspects of the investigation of

Dahl and Duke are discussed on p. 61. The thermal

decomposition of AgN03 has been studied by

Peltier and Duval [77] using thermogravimetric

technique. Results showed that AgN03 (m.p. 210 °C)

is thermally stable up to 473 °C, above which decomposition into NO2 , O2 and metallic Ag occurs. At 608 °C, decomposition is complete and pure

metallic silver remains. All the surface tension

measurements were carried out at temperatures

well below 473 °C and thus the stability of melt was

established.

The uncertainty for this salt is estimated to be

±1.0 percent.

Thallium Nitrate

[Classification: Group B; see table 69, p. 95 for

numerical values]

The surface tension of molten TINO3 has been

measured by Jaeger [46] and Addison and Coldrey

[19] (maximum bubble pressure technique) in the

temperature ranges 210 to 430 °C and 226 to 458 °C,

respectively. The values of Addison and Coldrey are recommended as the “best” values. Compared to the data of Addison and Coldrey, the results of

Jaeger show departure of 25 to 28 percent in the

temperature range 226 to 460 °C. This comparison

is illustrated in figure 28.

Some of the experimental aspects of the investigation of Addison and Coldrey [19] are discussed on p. 70. The thermal decomposition of TINOh has

been studied by Wendlandt [72] using thermogravimetric technique. Results showed that TINO3

FIGURE 27. Comparison of percent departures of the data for AgNO:i . — Dahl and Duke (1958) [18] O Addison and Coldrey (1961) [19] A Bertozzi and Sternheim (1964) [26] Bloom, Davis and James (1960) [1]

FIGURE 28. Comparison of percent departures of the data for

TlNO:i . — Addison and Coldrey (1961) [19] O Jaeger (1917) [46]

(m.p. 207 °C) is thermally stable up to 265 °C,

above which the anhydrous salt begins to lose

oxides of nitrogen. Between 460 and 505 °C, the

thermogravimetric curve exhibits a horizontal

weight level (the composition data did not corre- spond to oxides of thallium). At 505 °C, further

weight losses occurred and decomposition was

complete at 725 °C. Thus, it should be noted that

the two surface tension investigations were carried

out in and above the stability range of T1N03 and

the results should be viewed with some reservations.

The uncertainty for this salt is estimated to be

± 12 percent.

Ammonium Nitrate

[Classification: Group C; see table 70, p. 95 for

numerical values]

The surface tension of molten NH4 N03 has been

measured by Addison and Coldrey [19] (maximum

bubble pressure technique) in the temperature

range 170 to 220 °C.

The decomposition of molten NH4 N03 in the

range 180 to 280 °C was studied by Guiochon and

Jacque [75] using thermogravimetric technique.

Results showed that the loss in weight of NH4 N03 with time in this temperature range is attributed to two phenomena: evaporation and decomposition;

the latter is a first order jirocess with the rate constant k given by k = koe~ElRT

, where Ao=10n - 5 and E = 36,500 ± 1,800 cal. Condensation of the

salt vapor and of water vapor (a decomposition

product) was also observed.

The surface tension values, thus represent, in

part, that of decomposed melt and should be viewed

with reservations. An estimate of accuracy is not

possible due to insufficient information.

Calcium Nitrate, Strontium Nitrate, and

Barium Nitrate

[Classification: Group C; see table 71, p. 91 for

numerical values]

The surface tensions of molten Ca(N03 )2, and

Sr(N03 )2 and Ba(N03)> have been determined by

69
Addison and Coldrey [19] (maximum bubble pres- sure technique). For CafNOafi and SrfNOafi the

authors reported only one data point for each salt (101.5±0.4 dyne cm-1 at 560 °C and 128.4±0.5 dyne

cm -1at 615 °C respectively). The data for Ba(NC>3 )2 (11 points. 600 to 660 °C) are better represented by

a linear equation (y= 143.7 — 0.015/y 5 = 0.6 dyne

cm -1

). Some of the experimental details of the investigations of Addison and Coldrey, are as follows:

argon (purity, 99.98%), further purified by passage

through Linde molecular sieve (grade 4S), was used

as the bubbling gas; supermax glass vessels and

capillaries were used; analytical reagent grade

salts, dried at 110 °C for several hours, were used

without further purification.

The stabilities of the melts investigated are summarized as follows:

Ca(N03 ) 2 Sr(N03 )2 Ba(N03 ) 2

Clear, pale amber liquid, gas °C °c °C

evolution negligible

Small gas bubbles perceptible

550 605 595

in melt Gas evolution sufficient to in- terfere with surface tension560 615 630

measurement 575 635 675

Accuracy estimates are not possible for these

salts owing to insufficient information.

Sodium Nitrite

[Classification: Group B; see table 72, p. 95 for

numerical values]

The surface tension of molten NaNCL has been

determined by three groups [1, 19, 23] (maximum

bubble pressure method). The values of Addison

and Coldrey [1 9 1 are recommended as the “best'”

values in the range 291 to 384 °C. Compared to the

values of Addison and Coldrey, the results of Bloom,

Davis, and James [1] and Frame, Rhodes, and

Ubbelohde [23] show departures of —1.0 to —0.1

percent and 2.6 to 0.2 percent, respectively, in the

same temperature range. The departures are

illustrated in figure 29.

The experimental aspects of the investigations

of Addison and Coldrey [19] are discussed on p. NaN02 has been shown to be stable below 620 °C

by Freeman [78] using a thermogravimetric technique. At 620 °C, in the presence of CL, NaN02 undergoes partial oxidation and reaches a maximum

weight gain at 740 °C. At 780 °C, rapid decomposition occurs, and further increase of temperature

results in the formation of Na2 0 (at 920 °C).

The uncertainty for this salt is estimated to be

± 1.0 percent.

FIGURE 29. Comparison of percent departures of the data for NaN02 . — Addison and Coldrey (1961) [19] Q Frame, Rhodes and Ubbelohde (1959) [23] A Bloom. Davis and James (1960) [1]

Potassium Nitrite

[Classification: Group B, see table 73, p. 96 for

numerical values]

The surface tension of molten KN02 has been

determined by Addison and Coldrey [19], in the

range 450 to 501 °C (maximum bubble pressure

method). The data (7 points, 4 of which were obtained during the heating cycle and the other 3

during subsequent cooling of the melt) are better

represented by a linear equation with a precision,

s = 0.3 dyne cm-1

. Some of the experimental aspects of the investigation of the authors [19] are discussed on p. 70.

The uncertainty is estimated to be ± 1.0 percent.

Lithium Silicate

[Classification: Group B; see table 74, p. 96 for

numerical values]

The surface tension of LfiSiOa has been determined by Jaeger [46] (maximum bubble pressure

technique). The results (6 points, 1254 to 1601 °C)

are better represented by a quadratic equation with

a precision, 5 = 1.0 dyne cm-1. The experimental aspects of Jaeger’s investigation are discussed on p. 57. An accuracy esti- mate is not possible due to insufficient information.

Magnesium Metasilicate, Caleium Metasilicate,

Manganese Metasilicate, and Manganese

Orthosilicate

[Classification: Group C; see tables 75, 76, 77, and

78, pp, 96 and 97 respectively for numerical

values]

The method of maximum pull on cylinder has

been used by King [58] to measure the surface

tensions of these four silicates. The surface tensiontemperature equations used to generate the tabu70
lated values were obtained from the given temperature coefficients and the respective surface

tension values at 1570 °C. It is to be noted that the

coefficients are positive for these salts indicating an unusual behavior of temperature dependence for

surface tension.

Some of the experimental aspects of King’s

investigation are as follows: correction factors

applicable to the cylinder were determined using

liquids of known surface tension; all four silicates were synthesized by grinding the respective oxides

with Si02 and melting under nitrogen in graphite

crucibles using induction heating; the melts were

then cooled rapidly, ground, and ignited in oxygen

before use for the surface tension measurements;

iron crucibles were used for the manganese sili- cates to prevent reduction.

The pure oxides were obtained from the following

materials; Si02 , from rock quartz, ground and acid

washed; MnO, prepared from manganese oxalate

by heating in hydrogen and nitrogen (purity, 97.5

to 98.5%); CaO, obtained by ignition of A. R.

calcium carbonate; and MgO, pure, fused magnesia.

An accuracy estimate is not possible owing to insufficient information.

Lithium Metaphosphate,* Cesium Metaphosphate, Strontium Metaphosphate, and

Barium Metaphosphate

[Classification: Group C (except LiPO.3, Group B); see tables 79, 82, 84, and 85, pp. 97, 98, and 99

respectively for numerical values]

The surface tensions of molten LiP03 , CsP03 , Sr(P03 )2, and Ba(P03>2 have been determined by

Sokolova and Voskresenskaya [9] (maximum bubble

pressure technique). The data for these salts are represented as follows: LiP03 , 775 to 1072 °C,

y=206.1 —0.0222? ( 5 = 1.0 dyne cnr1 ); CsP03 , 737 to 1041 °C, 7 = 153.3 — 0.0487? (5 = 0.4 dyne

cm-1 ); Sr(P03 >2 , 1030 to 1082 °C, 7=233.7-0.00527?

(5 = 0.5 dyne cm-1

); Ba(P03 }2 , 902 to 1075 °C,

7 = 239.9 — 0.0177? (5 = 0.5 dyne cm-1

). The experimental aspects of Sokolova’s investigation are discussed on p. 58. The compounds were

prepared by thermal decomposition of the corre- sponding dihydrogenphosphates; the latter were first obtained by the action of H3 PO4 on carbonates of

the alkali-metals and hydroxides of the alkaline

earth-metals. (Analysis of the dihydrogenphosphates

by their various constituents yielded the following

results: Cs2 0/P2 05 = 1.00; SrO in Sr(H2 P04 )2 36.4% (theoretical, 36.79%), and Ba in Ba(H2 P04 )2, 46.0% (theoretical, 46.28%).)

The uncertainty of the surface tension data for

these four salts is estimated to be ±1.0 percent.

*Recent surface tension results of Nijjhar [17] (7 points, 745.5 to 1147.8 °C, y = 21 1. 70 ±0.42 — 0.02413 ± 0.00044c maximum pull on cylinder) showed departures

of 3 to 2 percent from Sokolova’s values in the same temperature range.

Sodium Metaphosphate

[Classification: Group A; see table 80, p. 97 for

numerical values]

Three different techniques have been used to measure the surface tension of NaP03 by five

groups; the ring method [28, 88], the maximum pull on cylinder method [27b] and the maximum bubble

pressure method [9, 46]. The results of Owens and

Mayer [88] are recommended as the “best” values

in the range 660 to 830 °C. The departures of the

values of the other investigators are illustrated in

figure 30.

Some of the experimental aspects of the investigation of Owens and Mayer [88] are as follows:

NaP03 was prepared by thermal dehydration of

reagent-grade NaH2 P04 at 520 °C for 1 week;

analysis of the product by the zinc oxide method

indicated a water content of less than 0.2 wt per- cent; a Du Nuoy tensiometer and a 6-cm platinumiridium ring were used and the appropriate corrections [66] were applied for the surface tension cal- culations.

The uncertainty is estimated to be ±0.1 percent.

Potassium Metaphosphate

[Classification: Group A; see table 81, p. 98 for

numerical values]

Two different techniques have been used to measure the surface tension of molten KP03 by

three groups; the maximum bubble pressure method

[9, 46] and the maximum pull on cylinder method

Figure 30. Comparison of percent departures of the data for NaPO,.* — Owens and Mayer (1964) [88] • Jaeger (1917) [46|

Callis, VanWazer and Metcalf (1955) [28] O Bradbury and Maddocks (1959) [27b] A Sokolova and Boskresenskaya (1963) [9]

*Reeent surface tension results of Nijjhar [17] (4 points, 808.4 to 1153.0 °C, 7 = 223.71 ±0.14 — 0.04882±0. 00014c maximum pull on cylinder) showed departures

of —2 to —3 percent from Owen’s values for the same temperature range.

71
[27a]. The values of Sokolova and Voskresenskaya

[9] are recommended as the “best” values in the

range 859 to 1082 °C. In the same range, the results

of Williams, Bradbury, and Maddocks [27a] show

departure of —4.9 to —4.7 percent while those of

Jaeger [46] show departure of 7.6 to 8.1 percent.

These are illustrated in figure 31.

The experimental aspects of the investigation

of Sokolova and Voskresenskaya are discussed on

p. 58. KPO3 was prepared by thermal decomposition of the dihydrogenphosphate (Analysis of P2O5

content in KPO3 yielded a value of 60.20 percent

(theoretical, 60.11%)).

Cesium Metaphosphate

(see under LiPCG, p. 71)

Calcium Metaphosphate

[Classification: Group B; see table 83, p. 98 for

numerical values]

The surface tension of molten CalPOsfi has been

measured by Sokolova and Voskresenskaya [9] (7 points, 1007 to 1110 °C, maximum bubble pressure) and by Bradbury and Maddocks [27b] (5 points,

1010 to 1110 °C, maximum pull on cylinder). The

authors reported their data only in the form of

equations; Sokolova, y — 240.6 — 0.01087 (5=0.8

dyne cm-1

) and Bradbury, y — 249.0 —0.0207 (5, not

given).

On the basis of other studies of Sokolova and

Voskresenskaya (e.g., NaCl) their results are recom- mended as the “best” values. The percent departure

FIGURE 31. Comparison of percent departures of the data for KP03 .* — Sokolova and Voskresenskaya (1963) [9] 0 Williams, Bradbury and Maddocks (1959) [27a] O Jaeger (1917) [46]

*Recent surface tension results of Nijjhar [17] (7 points. 853.5 to 1 156.6 °C, y = 204.25 ±0.33 — 0.06357 ± 0.00034c maximum pull on cylinder) showed departures of 3 to 2 percent from the values of Sokolova for the same temperature range.

of the values of Bradbury and Maddocks [27b]

varies from —0.4 to —0.8 percent in the same temperature range and is shown in figure 32.

The experimental aspects of Sokolova’s work are discussed on p. 58. Ca(P03 )2 was prepared by

thermal dehydration of CadTPO-ifi.

Strontium Metaphosphate

(see under LiPOj, p. 71)

Barium Metaphosphate

(see under LiPCG, p. 71)

Lithium Sulfate

[Classification: Group A; see table 86, p. 99 for

numerical values]

The surface tension of molten LbSCh has been

measured by Jaeger [46] and Semenchenko and

Shikhobalova [4] (maximum bubble pressure

method). The results of Jaeger (17 points, 860 to 1214 °C) are recommended as the “best” values.

Compared to Jaeger’s data, the results of Semenchenko and Shikhobalova show departure of 0.4

to 1.6 percent in the range 900 to 1100 °C. This

comparison is illustrated in figure 33.

13

1000 1040 1080 Temp (°C)

Figure 32. Comparison of percent departures of the data for Ca(P03 )2-* — Sokolova and Voskresenskaya (1963) [9] O Bradbury and Maddocks (1959) [27b]

FIGURE 33. Comparison of percent departure of the data for Li,S04 . - Jaeger (1917) [46] O Semenchenko and Shikhobalova (1947) [4]

* Recent surface tension results of Nijjhar [17] (9 points. 990.6 to 1 154.8 °C, y = 259. 18 ± 1.70 — 0.02622 ± 0.00156c maximum pull on cylinder) showed departures of 3 to

1 percent for the same temperature range.

72
Some of the experimental aspects of Jaeger’s

surface tension work are discussed on p. 57. The

thermal stability of Li2 S04 has been summarized

by Stern and Weise [731. Decomposition of Li2 S04 begins to be noticeable not far above its melting

point (859 °C), the Li2 0 product apparently dissolving in Li2 S04 while some volatilization of Li2 S04 occurs. No measurements of the decomposition

pressures have been made.

The uncertainty of the surface tension data is estimated to ± 1.0 percent.

Sodium Sulfate

[Classification: Group B; see table 87, p. 99 for

numerical values]

The surface tension of molten Na2 S04 has been

determined by Jaeger [46] (maximum bubble pres- sure technique). The data (5 points, 900 to 1077 °C)

are better represented by a quadratic equation

(y = 476.5 — 0.532t + 2.43 X 10_4

£

2

, 5=1.1 dyne

cm-1

). The thermal stability of Na2 S04 has been summarized by Stern and Weise [73]. Thermogravimetric analysis of Na2 S04 (m.p. 859 °C) showed

that the salt is stable up to 900 °C. At higher temperatures there is a weight loss (0.04% at 1000 °C;

1.051 at 1200 °C) and analysis of the residue in- dicated that loss in weight is due to both decomposition (because of alkaline properties) and

volatilization. This decomposition of Na2 S04 above

1000 °C may partially account for the deviation from

linear behavior of surface tension with temperature.

Some of the experimental aspects of Jaeger’s

investigation are as follows: Platinum capillaries

of radii 0.04935 to 0.05025 cm were used. Nitrogen,

the bubbling gas, obtained by heating aqueous

solutions of NaN02 and NH4 C1, was purified by

passing respectively through alkaline-pyrogallol

solution, concentrated H2 S04 and P2 05 ; it was

preheated to the melt temperature before passing

through the capillary system; no details were given

for the preparation and purification of the salt. An accuracy estimate is not possible owing to insufficient information. It should be noted that

most of Jaeger’s data are 2 to 8 percent higher than

those redetermined from more recent studies, and

that for certain compounds the differences are

significantly larger, e.g., NaF, 10 percent; K2 Cr2 07 , 10 to 20 percent; TINO3, 25 to 28 percent.

Potassium Sulfate

[Classification: Group A; see table 88, p. 99 for

numerical values]

The surface tension of molten K2 S04 has been

measured by three groups [6, 13, 46] (maximum

bubble pressure technique). The results of Neith- amer and Peake [6] (14 points 1099 to 1121 °C) are recommended as the “best” values. Compared to

the data of Neithamer and Peake, the results of

Jaeger [46] and Sokolova and Voskresenkaya [13]

show departures of 1.5 to 3.0 percent and —4.0 to — 4.5 percent respectively in the same temperature

range. This comparison is illustrated in figure 34.

Some of the experimental aspects of the investigation of Neithamer and Peake are as follows:

purified nitrogen was used as the bubbling gas; the

tips of the platinum-alloy capillaries were checked

periodically; all other necessary precautions as out- lined in section 3.2 for the maximum bubble pres- sure method were taken.

The thermal stability of K2 S04 (m.p. 1069 °C)

has been summarized by Stern and Weise [73].

Thermogravimetric analysis showed that K2 S04 is stable up to 900 °C. At 1000 °C, a slight loss in

weight was observed (attributed to sublimation).

At higher temperature there is a weight loss (e.g.,

3.6% at 1200 °C); subsequent analysis of the residue

(no alkaline reaction or change in percentage

composition) confirmed that all weight loss was at- tributed to volatilization and none to decomposition.

The uncertainty of the surface tension data for

this salt is estimated to be ± 0.5 percent.

Rubidium Sulfate and Cesium Sulfate

[Classification: Group B; see tables 89 and 90,

p. 100 for numerical values]

The surface tensions of these two alkali metal

sulfates have been measured by Jaeger [46] (maximum bubble pressure technique). The data for

Rb2 S04 (ll points, 1085 to 1545 °C) and Cs2 S04 (11 points, 1036 to 1530 °C) are better represented

by quadratic equations (5=0.3 dyne cm-1 and

5=0.4 dyne cm-1

, respectively).

The experimental aspects and the accuracy esti- mates of Jaeger’s surface tension work are discussed on p. 73. The thermal stabilities of these two alkali

sulfates have been summarized by Stern and Weise

[73]. Thermogravimetric analysis of the salts showed

that Rb2 S04 (m.p. 1074 °C) is stable up to 900 °C

while Cs2 S04 (m.p. 1019 °C) is stable up to 800 °C.

At higher temperatures there were weight losses

(0.3% at 1000 °C and 6.3% at 1200 °C) for Rb,S04 ; 0.2% at 900 °C, 0.87% at 1000 °C, and 13.9% at 1200 °C for Cs2 S04 ) which were confirmed by analyTemp (°C) FIGURE 34. Comparison of percent departures of the data for

K..SO4. — Neithamer and Peake (1961) [6] O Jaeyer (1917) [46] Sokolova and Voskresenskaya (1962) [13]

73
sis to be due to volatilization and not due to decomposition (absence of alkaline properties in the

residue).

Sodium Molybdate and Potassium Molybdate

[Classification: Group B; see tables 91 and 92,

p. 101 for numerical values]

The surface tensions of these two alkali molybdates have been determined by Jaeger [46] (maximum bubble pressure technique). The data for both

Na2 Mo04 (14 points, 698 to 1212 °C) and K2 Mo04 (12 points, 930 to 1522 °C) are better represented

by quadratic equations (5=0.6 dyne cm-1 and

5=0.4 dyne cm-1

, respectively).

The experimental aspects and the accuracy esti- mates of Jaeger's surface tension work are discussed on p. 73.

Lead Molybdate and Bismuth Molybdate

[Classification: Group B; see tables 93 and 94,

pp. 101 and 102 respectively for numerical values]

The surface tensions of these two molten molybdates have been determined by Morris, McNair

and Koops [24] (pin method). The data for PbMo04 (4 points, 1093 to 1124 °C) and Bi2 (Mo04 )3 (5 points,

680 to 760 °C) are represented respectively by a linear equation (5 = ±0.9 dyne cm-1

) and a quadratic equation (5 = ±0.6 dyne cm-1

). Spectroscopic examinations [24] of the anhydrous

salts revealed that both salts were of analytical

reagent quality. Accuracy estimates of the surface

tension data for these two salts are not possible

due to insufficient information.

Sodium Tungstate and Potassium Tungstate

[Classification: Group B; see tables 95 and 96.

p. 102 for numerical values]

The surface tensions of these two alkali tungstates

have been determined by Jaeger [46] (maximum

bubble pressure technique). The data for both

Na2 W04 (20 points, 710 to 1595 °C) and K2 W04 (15 points, 925 to 1520 °C) are better represented

by quadratic equations with precisions (5=0.7

dyne cm-1 and 5 = 0.6 dyne cm-1 respectively).

The experimental aspects and the uncertainty

estimates of Jaeger's surface tension work are discussed on p. 73.

Potassium Thiocyanate and Potassium

Chlorate

[Classification: Group C; see table 97, p. 102 for

numerical values]

The surface tensions of molten KCNS and KC10;! have been determined by Frame, Rhodes and

Ubbelohde [23] (maximum bubble pressure technique). For KCNS, the freshly prepared melt

showed a temperature dependence of — 1.36 dyne

cm-1 deg-1

; after a certain time (period of time was

unspecified) the value changed to 0.14 dyne cm-1 deg-1

. The two surface tension-temperature equations for KCNS accordingly are: y= 339.5— 1.36t

(freshly prepared melt); y— 126.0 — 0.14f (aged

melt). Both equations yield the same value (y= 101.5

dyne cm-1

) at the melting point (175 °C). KCIO3 decomposes with the formation of KC1: after a period of 4 days as much as 2 percent KC1 was

formed. The large variation of surface tensions

with temperature and also with the age of the melt was partly attributed to decomposition.

Some of the experimental details of the investigation of Frame et al. are as follows: KCNS and

KCIO3 (A.R. grade) were used without further

purification. Nitrogen (02 content < 1 p.p.m.;

B.O.C. “white spot") dried in a liquid oxygen trap

was used as the bubbling gas for KCNS melt.

Oxygen (B.O.C. cylinder gas) dried in a similar

manner, was used for KCIO3 . The bubbling rates were comparatively low (2 to 8 min per bubble).

The gases were preheated to the temperatures of

the melts by passing through a preheater immersed

in a nitrate-nitrite bath, thermostatically controlled by a thyratron bridge circuit to ±0.05 °C.

The uncertainty for both salts is estimated to be

± 2.0 percent.

Potassium Diehromate

[Classification: Group B: see table 98. p. 103, for

numerical values]

The surface tension of molten K2 Cr2 0: has been

determined by Jaeger [46] and Frame. Rhodes, and

Ubbelohde [23] (maximum bubble pressure technique) in the temperature ranges 420 to 535 °C.

and 400 to 440 °C, respectively. The results of

Frame et al. are recommended as the "best" values.

The values of Jaeger show departures of 9 to 16

percent in the range 400 to 440 °C. This comparison

is illustrated in figure 35.

Figure 35. Comparison of percent departure of the data for

k,Cr>()7 . — Frame. Rhodes and Ubbelohde (1959) [23) O Jaeger (1917) [46]

74
The experimental aspects of the investigation of

Frame et al. are discussed on p. 74. K2 Cr207 (A.R.

grade), twice recrystallized from conductivity water, was air-dried at 180 °C for 48 hr, followed by

thermal shock drying.

The uncertainty is estimated to be ±2.0 percent.

Lithium Chlorate

[Classification: Group B; see table 99, p. 103 for

numerical values]

The surface tension of molten LiClCL has been

determined by Campbell and Williams [68] (capillary rise technique). The results (6 points, 132 to 162° C) are represented by a linear equation

(5=0.1 dyne cm-1

). Lithium chlorate is extremely

hydroscopic; the authors have taken due precautions in preparing and handling the salt. An accuracy estimate is not possible owing to insufficient information.

Sodium Chlorate

[Classification: Group B; see table 100, p. 103, for

numerical values]

The surface tension of molten NaCICL has been

determined by Campbell and van Der Kouwe [21]

(capillary technique). The results (6 points, 265 to 290 °C) can best be represented by a linear equation

(5=0.4 dyne cm-1

). No estimate of accuracy was

attempted owing to insufficient information.

List of Tables

FLUORIDES

LiF 3 NaF 4 KF 5 RbF 6 CsF 7 ThF4 8 UF4 9 UF6 10 Na3AlF6 11 CHLORIDES

LiCl 12 NaCl 13 KC1 14 RbCl 15 CsCl 16 CuCl 17 AgCl 18 MgCl2 19 CaCl2 20

SrCl2 21 BaCl2 22 ZnCl2 23 CdCl2 24 SnCl2 25 HgCl2 26

PbCl2 27

AlCfi 28

GaCl3 29

GaCL • 2C5 H,oNH 30

GaCL • C3 H10NH 30

GaCh • C5 H5 N 30

BiCl3 31 BROMIDES

NaBr 32 KBr 33 RbBr 34

CsBr 35 AgBr 36 CaBr2 37 SrBr2 38 BaBr2 39 ZnBr2 40

CdBr2 41 HgBr2 26

BiBr.a 42

Table

Lithium fluoride Sodium fluoride Potassium fluoride Rubidium fluoride Cesium fluoride Thorium tetrafluoride. Uranium tetrafluoride Uranium hexafluoride

Cryolite

Lithium chloride Sodium chloride Potassium chloride Rubidium chloride Cesium chloride Cuprous chloride

Silver chloride Magnesium chloride ,... Calcium chloride Strontium chloride Barium chloride Zinc chloride Cadmium chloride Stannous chloride Mercuric chloride Lead chloride Aluminium chloride Gallium chloride Gallium trichloride, piperidine complex (1:2) Gallium trichloride, piperidine complex (1:1) Gallium trichloride, pyridine complex (1:1)... Bismuth trichloride

Sodium bromide

Potassium bromide.

Rubidium bromide.

Cesium bromide

Silver bromide

Calcium bromide...

Strontium bromide.

Barium bromide

Zinc bromide

Cadmium bromide..

Mercuric bromide..

Bismuth tribromide

Page

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81

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82

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83

8384

84

84

8484

84

85

85

8585

86

8686

86

87

87

8387

335-493 0-69—6 75
Table Page IODIDES

Nal 43 Sodium iodide 87 KI 44 Potassium iodide 88 Rbl 45 Rubidium iodide 88

Csl 46 Cesium iodide 88 Cal2 47 Calcium iodide 89

Srl2 48 Strontium iodide 89 Bal2 49 Barium iodide 89 OXIDES B2 03 50 Boron trioxide 90

A12 03 51 Aluminum oxide 90

Si02 52 Silicon dioxide 90

Ge02 53 Germanium dioxide 91 PbO 51 Lead oxide 90 P2 03 54 Phosphorus trioxide 91 P205 55 Phosphorus pentoxide 91 FeO 51 Ferrous oxide 90

SULFIDES

Cu2 S 17 Cuprous sulfide 81 T12 S 56 Thallium sulfide 91 METABORATES

LiB02 57 Lithium metaborate 92 NaB02 58 Sodium metaborate 92 KB02 59 Potassium metaborate 92 CARBONATES

Li2 C03 60 Lithium carbonate 93 Na2 C03 61 Sodium carbonate 93 K2 C03 62 Potassium carbonate 93 NITRATES

LiN03 63 Lithium nitrate 93 NaN03 64 Sodium nitrate 93 KN03 65 Potassium nitrate 94

RbN03 66 Rubidium nitrate 94

CsN03 67 Cesium nitrate 94

AgN03 68 Silver nitrate 94

T1N03 69 Thallium nitrate 95 NH4 N03 70 Ammonium nitrate 95 Ca(N03)2 71 Calcium nitrate 95 Sr(N03)2 71 Strontium nitrate 95 Ba(N03 )2 71 Barium nitrate 95

NITRITES

NaN02 72 Sodium nitrite 95

KN02 73 Potassium nitrite 96

SILICATES

Li2 Si03 74 Lithium silicate 96 MgSi03 75 Magnesium metasilicate 96 CaSi03 76 Calcium metasilicate 96 MnSi03 77 Manganese metasilicate 97

Mn2 Si04 78 Manganese orthosilicate 97

METAPHOSPHATES

LiP03 79 Lithium metaphosphate 97 NaP03 80 Sodium metaphosphate 97

KP03 81 Potassium metaphosphate 98

CsP03 82 Cesium metaphosphate 98

Ca(P03)2 83 Calcium metaphosphate 98

Sr(P03)2 84 Strontium metaphosphate 98 Ba(P03)2 85 Barium metaphosphate 99

76
Table Page SULFATES

Li2 S04 86 Lithium sulfate 99 Na2 S04 87 Sodium sulfate 99 K2 SCL 88 Potassium sulfate 99

Rb2 S04 89 Rubidium sulfate 100 Cs2 S04 90 Cesium sulfate 100 MOLYBDATES

Na2 Mo04 91 Sodium molybdate 101 K2 Mo04 92 Potassium molybdate 101 PbMo04 93 Lead molybdate 101 Bi2 (Mo04 )3 94 Bismuth molybdate 102 TUNGSTATES

Na2 W04 95 Sodium tungstate 102 K2 W04 96 Potassium tungstate 102 MISCELLANEOUS

KCNS 97 Potassium thiocyanate 102 KC103 97 Potassium chlorate 102 K2 Cr2 07 98 Potassium dichromate 103 LiC103 99 Lithium chlorate 103 NaClOs 100 Sodium chlorate 103

77
6. Numerical Values of Surface Tension

Table 3. Lithium fluoride, LiF

mp 845 °C

[Classification: Group A: for discussion see p. 55.]

y = 319.5 — 0.0988t (5=0.7 dyne cm-1

)

°c 7 °C 7

880 232.6 1080 212.8

900 230.6 1100 210.8

920 228.6 1120 208.8

940 226.6 1140 206.9

960 224.7 1160 204.9

980 222.7 1180 202.9

1000 220.7 1200 200.9

1020 218.7 1220 199.0

1040 216.8 1240 197.0

1060 214.8 1260 195.0

Reference: y, [37, 46].

Melting Point: [69],

Table 4. Sodium fluoride, NaF

mp 980 °C

[Classification: Group A; for discussion see p. 56.]

y = 267.2 — 0.082t

°C y

1000 185.2

1010 184.4

1020 183.6

1030 182.7

1040 181.9

1050 181.1

1060 180.3

1070 179.5

1080 178.6

Table 5. Potassium fluoride

,

KF

mp 856 °C

[Classification: Group B; for discussion see p. 57.]

y= 176.2 -0.0108t-0.333 X 10~4

t 2 (5=0.3 dyne cm-')

°C 7 °C 7 °C 7

920 138.1 1060 127.3 1200 115.3

940 136.6 1080 125.7 1220 113.5

960 135.1 1100 124.0 1240 111.6

980 133.6 1120 122.3 1260 109.7

1000 132.1 1140 120.6 1280 107.8

1020 130.5 1160 118.9 1300 105.9

1040 129.0 1180 117.1

Reference: y, [46]

Melting Point: [69].

TABLE 6. Rubidium fluoride, RbF

mp 775 °C

[Classification: Group A; for discussion see p. 57.]

y= i87.6 — 0.0782t ( 5 = 1.7 dyne cm-1

)

°C 7 °C 7 °C 7

800 125.0 870 119.6 940 114.1

810 124.3 880 118.8 950 113.3

820 123.5 890 118.0 960 112.5

830 122.7 900 117.2 970 111.8

840 121.9 910 116.4 980 111.0

850 121.1 920 115.7 990 110.2

860 120.4 930 114.9 1000 109.4

Reference: y, [37 , 46]. Melting Point: [69], Reference: y, [32, 37, 46],

Melting Point: [69],

78
Table 7. Cesium fluoride

,

CsF

mp 681 °C

[Classification: Group A; for discussion see p. 57.]

y = 162.5 — 0.0808J (5 = 0.7 dyne cm-1

)

°c y °C y °C y

720 104.3 810 97.1 900 89.8

730 103.5 820 96.2 910 89.0

740 102.7 830 95.4 920 88.2

750 101.9 840 94.6 930 87.4

760 101.1 850 93.8 940 86.5

770 100.3 860 93.0 950 85.7

780 99.5 870 92.2 960 84.9

790 98.7 880 91.4 970 84.1

800 97.9 890 90.6 980 83.3

Reference: y, [37, 46]

Melting Point: [69],

Table 8. Thorium tetrafluoride, ThF^

mp 1110 °C

[Classification: Group C; for discussion see p. 57.]

y — 416.9 — 0.161f (s=2.5 dyne cm-1

)

°C y °C y

1160 230.2 1420 188.3

1180 227.0 1440 185.1

1200 223.8 1460 181.9

1220 220.5 1480 178.7

1240 217.3 1500 175.5

1260 214.1 1520 172.2

1280 210.9 1540 169.0

1300 207.7 1560 165.8

1320 204.4 1580 162.6

1340 201.2 1600 159.4

1360 198.0 1620 156.1

1380 194.8 1640 152.9

1400 191.6 1660 149.7

Reference: y, [70].

Melting Point: [70],

Table 9. Uranium tetrafluoride, UF4

mp 1036 °C

[Classification: Group C; for discussion see p. 57.]

y = 394.5 — 0.192t (5 = 2.5 dyne cm-1

)

°C y °C y °C y

1060 191.0 1180 167.9 1300 144.9

1080 187.1 1200 164.1 1320 141.1

1100 183.3 1220 160.3 1340 137.2

1120 179.5 1240 156.4 1360 133.4

1140 175.6 1260 152.6 1380 129.5

1160 171.8 1280 148.7 1400

1420

125.7

121.9

Reference: y, [70]

.

Melting Point: [70],

Table 10. Uranium hexafluoride, UF«

mp 64 °C

[Classification: Group C; for discussion see p. 57.]

Reference: y. [50 ]

.

Melting Point: [69], *The two tabulated values are the experimental points

Table 11. Cryolite, Na3AlFfi mp 1000 °C

[Classification: Group C; for discussion see p. 57.]

y = 262.0 — 0. 128/ (5=1.9 dyne cm-1

)

°C y

1000 134.0

1010 132.7

1020 131.4

1030 130.2

1040 128.9

1050 127.6

1060 126.3

1070 125.0

1080 123.8

79

Reference: y, [32]

.

Melting Point: [69]

.
Table 12. Lithium chloride, LiCl

mp 610 °C

[Classification: Group A; for discussion see p. 57.]

y — 164.5 — 0.0583^ (s = 0.3 dyne cm-1

)

°c 7 °C 7 °C y

620 128.4 710 123.1 800 117.9

630 127.8 720 122.5 810 117.3

640 127.2 730 121.9 820 116.7

650 126.6 740 121.4 830 116.1

660 126.0 750 120.8 840 115.5

670 125.4 760 120.2 850 114.9

680 124.9 770 119.6 860 114.4

690 124.3 780 119.0 870 113.8

700 123.7 790 118.4

Reference: y, [37, 46].

Melting Point: [69],

Table 13. Sodium chloride, NaCl

mp 800 °C

[Classification: Group A; for discussion see p. 57.]

y = 171.5-0.0719t(5 = 0.2 dyne cnr1

)

°C y °C y

810 113.3 890 107.5

820 112.5 900 106.8

830 111.8 910 106.1

840 111.1 920 105.4

850 110.4 930 104.6

860 109.7 940 103.9

870 109.0 950 103.2

880 108.2 960 102.5

970 101.8

Reference: y, [1, 4, 7, 13, 10, 45, 46, 60],

Melting Point: [69],

TABLE 14. Potassium chloride, KC1

mp 770 °C

[Classification: Group A; for discussion see p. 58.]

y = 160.4 — 0.0770r (s = 0.4 dyne cm-1

)

°C y °C 7

780 100.3 880 92.6

790 99.6 890 91.9

800 98.8 900 91.1

810 98.0 910 90.3

820 97.3 920 89.6

830 96.5 930 88.8

840 95.7 940 88.0

850 95.0 950 87.3

860 94.2 960 86.5

870 93.4 970 85.7

Reference: y, [1, 4, 6, 10, 12, 29, 40, 45, 46, 60,

31al. Melting Point: [69].

Table 15. Rubidium chloride, RbCl mp 715 °C

[Classification: Group A; for discussion see p. 58.]

y= 162.2- 0.0904* + 0.0239 X 10~4

;

2 (5 = 0.2 dyne cm-')

°C 7 °C 7 °C 7 °C 7

760 94.9 860 86.2 960 77.6 1060 69.1

770 94.0 870 85.4 970 76.8 1070 68.2

780 93.1 880 84.5 980 75.9 1080 67.4

790 92.3 890 83.6 990 75.0 1090 66.5

800 91.4 900 82.8 1000 74.2 1100 65.7

810 90.5 910 81.9 1010 73.3 1110 64.8

820 89.7 920 81.1 1020 72.5 1120 64.0

830 88.8 930 80.2 1030 71.6 1130 63.1

840 88.0 940 79.3 1040 70.8 1140 62.3

850 87.1 950 78.5 1050 69.9 1150 61.4

Reference: y, [4, 45, 46] . Melting Point: [69],

80
Table 16. Cesium chloride, CsCl mp 645 °C

[Classification: Group A; for discussion see p. 58.]

|/= 112.5 -0.00932?- 0.391 X 10~4

?

2

(s = 0.4 dyne cm-*)

Reference: y, [4, 29, 45, 461 . Melting Point: [69].

Table 17. Cuprous chloride and cuprous sulfide

Cuprous chloride, CuCl* mp 430 °C

[Classification: Group C; for discussion see p. 59.]

°c y

450 92

Cuprous sulfide, Cu2 S* mp 1127 °C

[Classification: Group C; for discussion see p. 59.]

°C y

1150 410

^Reference: y, 1 921 . Melting Point: [69].

Table 18. Silver chloride, AgCl

mp 455 °C

[Classification: Group C; for discussion see p. 59.]

7 = 202.2 — 0.052? (s = 0.8 dyne cm-1

)

°C y °C y °C y

460 178.3 540 174.1 620 170.0

470 177.8 550 173.6 630 169.4

480 177.2 560 173.1 640 168.9

490 176.7 570 172.6 650 168.4

500 176.2 580 172.0 660 167.9

510 175.7 590 171.5 670 167.4

520 175.2 600 171.0 680 166.8

530 174.6 610 170.5 690

700

166.3

165.8

Reference: y, [14].

Melting Point: [69],

Table 19. Magnesium chloride, MgCl2 mp 714 °C

[Classification: Group C; for discussion see p. 59.]

y = 74.0-0.010?

°C y °C y

720 66.8 830 65.7

730 66.7 840 65.6

740 66.6 850 65.5

750 66.5 860 65.4

760 66.4 870 65.3

770 66.3 880 65.2

780 66.2 890 65.1

790 66.1 900 65.0

800 66.0 910 64.9

810 65.9 920 64.8

820 65.8 930 64.7

Reference: y, [40, 60, 10].

Melting Point: [69],

81
TABLE 20. Calcium chloride

,

CaCl2 mp 782 °C

[Classification: Group A; for discussion see p. 60.]

y = 203.9 — 0.-0728? (s = 0.4 dyne cm-1

)

°c y °C 7

770 147.8 850 142.0

780 147.1 860 141.3

790 146.4 870 140.6

800 145.7 880 139.8

810 144.9 890 139.1

820 144.2 900 138.4

830 143.5 910 137.7

840 142.8 920 136.9

Reference: y, [7, 29, 37]

Melting Point: [69],

Table 21. Strontium chloride, SrCl>

mp 875 °C

[Classification: Group B; for discussion see p. 60.]

y = 215.9 — 0.0541? (5=1.0 dyne cm-1)

°C y °C y

880 168.4 970 163.5

890 167.8 980 163.0

900 167.3 990 162.4

910 166.8 1000 161.9

920 166.2 1010 161.4

930 165.7 1020 160.8

940 165.1 1030 160.3

950

960

164.6

164.1

1040 159.7

Reference: y, [34]

Melting Point: [69],

Table 22. Barium chloride, BaCL

mp 962 °C

[Classification: Group A; for discussion see p. 60.] y = 241. 6 — 0.0790? (5 = 0.3 dyne cm-1

)

°C y

970 165.0

980 164.2

990 163.4

1000 162.6

1010 161.8

1020 161.0

1030 160.2

1040 159.4

Reference: y, [12, 13].

Melting Point: [69],

Table 23. Zinc chloride, ZnCl2 mp 283 °C

[Classification: Group C; for discussion see p. 60.]

y = 54.4 — 0.00199? ( 300-550' °C) (5= 1.1 dyne cm-')

y = 63.6 — 0.0190t (550-700 °C) (5 = 0.6 dyne cm- 1 )

°C y °C y °C y

300 53.80 420 53.56 550 53.2

310 53.78 430 53.54 560 53.0

320 53.76 440 53.52 570 52.8

330 53.74 450 53.50 580 52.6

340 53.72 460 53.48 590 52.4

350 53.70 470 53.46 600 52.2

360 53.68 480 53.44 610 52.0

370 53.66 490 53.42 620 51.8

380 53.64 500 53.40 630 51.6

390 53.62 510 53.39 640 51.4

400 53.60 520 53.37 650 51.2

410 53.58 530 53.35 660 51.0

540 53.33 670 50.8

680 50.6

690 50.4

700 50.2

Reference: y [39]

Melting Point: [69],

82
Table 24. Cadmium chloride, CdCl2 mp 568 °C

[Classification: Group B; for discussion see p. 61. | y = 74. 15 + 0.0459f — 0.492 X 10-4

t 2 (s — 0.3 dyne cm-1

)

°c 7 °C y °C y

580 84.22 690 82.40 810 79.05

590 84.10 700 82.17 820 78.71

600 83.98 710 81.94 830 78.35

610 83.84 720 81.69 840 77.99

620 83.70 730 81.44 850 77.62

630 83.54 740 81.17 860 77.24

640 83.37 750 80.90 870 76.84

650 83.20 760 80.62 880 76.44

660 83.01 770 80.32 890 76.03

670 82.82 780 80.02v 900 75.61

680 82.61 790 79.71 910 75.18

800 79.38 920 74.74

Reference: y [35]

.

Melting Point: [69],

TABLE 25. Stannous chloride, SnCl2 mp 245 °C

[Classification: Group A; for discussion see p. 61.]

y = 128.0 — 0.0984f (5 = 2.7 dyne cm-1

)

°C y °C y °C y

280 100.6 350 93.7 420 86.8

290 99.6 360 92.7 430 85.9

300 98.6 370 91.7 440 84.9

310 97.6 380 90.8 450 83.9

320 96.6 390 89.8 460 82.9

330 95.7 400 88.8 470 81.9

340 94.7 410 87.8 480 81.0

Table 26. Mercuric chloride and mercuric bromide

Mercuric chloride, HgCl2 * mp 277 °C

[Classification: Group C; for discussion see p. 61

°C y

293 56.1

Mercuric bromide HgBr2 * mp 241 °C

[Classification: Group C; for discussion see p. 61

*Reference: y, [59].

Melting Point: [69],

Table 27. Lead chloride, PbCl2 mp 498 °C

[Classification: Group B; for discussion see p. 61.]

y = 199.8 — 0.124f (5 = 0.7 dyne cm ')

°C 7

520 135.3

530 134.1

540 132.8

550 131.6

560 130.4

570 129.1

580 127.9

Reference: y, [3fi, 46],

Melting Point: [69].

Reference: y, [1, 3C 10]

Melting Point: [69].

83
TABLE 28. Aluminum chloride, AICI3 Table 30. [Classification: Group C; for discussion see p. 62.]

mp 192.5 °C

[Classification: Group B; for discussion see p. 62.]

7 = 23.20 — 0.0704? (s = 0.2 dyne cm-1

)

Reference: 7, [61].

Melting Point: [69],

Table 29. Gallium chloride, GaCl3 mp 77.9 °C

[Classification: Group A; for discussion see p. 62.]

7 = 34.97 — 0.0997? (5 = 0.1 dyne cm -1

)

A. Gallium trichloride — Piperidine complex (1:2)

GaCl3 -2C5 HioNH

mpll2°C 7 = 46.0 — 0.16? (5 = 0.2 dyne cm-1

)

B. Gallium trichloride — Piperidine complex (1:1)

GaCh-CsHioNH

mp 134 °C 7 = 45.5 — 0.084? (5 = 0.5 dyne cm-1

)

C. Gallium trichloride — Pyridine complex (1:1)

GaCl3 -C5 H5 N

mp 126 °C 7 = 50.3-0.097? (5 = 0.5 dyne cm'1 )

°c 7a 7b 7c

120 25.9

130 24.3 37.7

140 22.6 33.6 36.7

150 21.0 32.8 35.8

160 19.3 31.9 34.8

Reference: 7, [43, 42].

Melting Point: [43,42].

°C 7

80 26.99

90 25.99

100 25.00

no 24.00

120 23.01

130 22.01

140 21.01

Reference: 7, [44, 61].

Melting Point: [69].

TABLE 31. Bismuth trichloride, BiCl3 mp 232 °C

[Classification: Group B; for discussion see p. 62.]

7= 114.0-0.210? + 1.243 X IO-4

?2

(5 = 0.1 dyne cm-'

°C 7

270 66.36

280 64.95

290 63.55

300 62.19

310 60.85

320 59.53

330 58.24

340 56.97

350 55.73

360 54.51

370 53.32

380 52.15

Reference: 7, [46]

Melting Point: [69],

84
Table 32. Sodium bromide

,

NaBr mp 750 °C

[Classification: Group A; for discussion see p. 62.]

y = 164.8 — 0.0809t (5 = 0.8 dyne cm-1

)

Table 34. Rubidium bromide, RbBr mp 680 °C

[Classification: G*oup B; for discussion see p. 63.]

y — 138.0 — 0.0720t (5 = 0.2 dyne cm-1

)

°c y °C y

760 103.3 840 96.8

770 102.5 850 96.0

780 101.7 860 95.2

790 100.9 870 94.4

800 100.1 880 93.6

810 99.3 890 92.8

820 98.5 900 92.0

830 97.7

Reference: y [1, 13, 45, 46],

Melting Point: [69],

Table 33. Potassium bromide, KBr mp 735 °C

[Classification: Group A; for discussion see p. 63.]

y= 142.2 — 0.072f (5 = 0.2 dyne cm-1

)

°C y °C y

750 88.2 850 81.0

760 87.5 860 80.3

770 86.8 870 79.6

780 86.0 880 78.8

790 85.3 890 78.1 800 1 84.6 900 77.4

810 83.9 910 76.7

820 83.2 920 76.0

830 82.4 930 75.2

840 81.7 940 74.5

950 73.8

Reference: y [1_, 36, 45, 46],

Melting Point: [69].

°C y °C y

720 86.2 780 81.8

730 85.4 790 81.1

740 84.7 800 80.4

750 84.0 810 79.7

760 83.3 820 78.9

770 82.6 830 78.2

Reference: y [45, 46].

Melting Point: [69],

Table 35. Cesium bromide, CsBr

mp 636 °C

[Classification: Group B; for discussion see p. 63.]

y = 127. 1 — 0.068f (5 = 0. 1 dyne cm-1

)

°C y °C y

660 82.22 760 75.42

670 81.54 770 74.74

680 80.86 780 74.06

690 80.18 790 73.38

700 79.50 800 72.70

710 78.82 810 72.02

720 78.14 820 71.34

730 77.46 830 70.66

740 76.78

750 76.10

Reference: y [45, 46],

Melting Point: [69],

85
Table 36. Silver bromide, AgBr

mp 430 °C

[Classification: Group C: for discussion see p. 59.J 7=164.5 — 0.025? (5 = 0.7 dyne cm-1

)

Table 38. Strontium Bromide, SrBr2

mp 643 °C

[Classification: Group B: for discussion see p. 64.]

y = 178.0 — 0.0439? (5= 1.5 dyne cm-1

)

°c y

460 153.0

470 152.8

480 152.5

490 152.3

500 152.0

510 151.8

520 151.5

530 151.3

540 151.0

550 150.8

560 150.5

570 150.3

580 150.0

590 149.8

600 149.5

610 149.3

620 149.0

Reference: y [14]

Melting Point: [69],

°C y °C y °C y

680 148.2 790 143.3* 900 138.5

690 147.7 800 142.9 910 138.1

700 147.3 810 142.4 920 137.6

710 146.8 820 142.0 930 137.2

720 146.4 830 141.6 940 136.7

730 145.9 840 141.1 950 136.3

740 145.5 850 140.7 960 135.9

750 145.1 860 140.3 970 135.4

760 144.6 870 139.8 980 134.9

770 144.2 880 139.4 990 134.5

780 143.8 890 138.9 1000

1010

134.1

133.7

Reference: y. [34],

Melting Point: [69],

Table 39. Barium bromide, BaBr2 mp 850 °C

[Classification: Group B: for discussion see p. 64.]

7 = 207.6 — 0.0644? (5=1.2 dyne cm-1

)

Table 37. Calcium bromide, CaBr2 mp 730 °C

[Classification: Group B: for discussion see p. 61.]

7=153.1—0.0459? (5 = 0.3 dyne cm'1 )

°C 7

770 117.8

780 117.3

790 116.8

800 116.4

810 115.9

Reference: 7 [35]

Melting Point: [69],

°C y

870 151.6

880 150.9

890 150.3

900 149.6

910 149.0

920 148.4

930 147.7

940 147.1

950 146.4

960 145.8

970 145.1

980 144.5

990 143.8

1000 143.2

1010 142.6

Reference: 7, [34]

Melting Point: [69],

86
Table 40. Zinc bromide, ZnBr2 mp 394 °C

[Classification: Group C; for discussion see p. 64.

|

7 = 58.1—0.0172? (500-600 °C) (5 = 0.7 dyne cm-1

) 7 = 100.5 — 0.0895? (600-670 °C) (5 = 0.08 dyne cm-1

)

°c y °C y

500 49.50 610 45.9

510 49.33 620 45.0

520 49.16 630 44.1

530 48.98 640 43.2

540 48.81 650 42.3

550 48.64 660 41.4

560 48.47 670 40.5

570 48.30

580 48.12

590 47.95

600 47.78

Reference: 7 , [39]

.

Melting Point: [69],

Table 41. Cadmium bromide, CdBr2 mp 568 °C

[Classification: Group B; for discussion see p. 64.]

7 = 16.12 + 0.167? — 0.143 X 10-3

?

2

( 5 = 1.0 dyne cm"1 )

°C y °C y

630 64.57 710 62.60

640 64.43 720 62.23

650 64.25 730 61.83

660 64.05 740 61.39

670 63.82 750 60.93

680 63.56 760 60.44

690 63.27 770 59.93

700 62.95 780 59.38

Reference: 7 , [37].

Melting Point: [69],

Table 42. Bismuth tribromide, BiBr.j

mp 218 °C

[Classification: Group B; for discussion see p. 64.]

7 = 90. 18 -0.0871?- 0.284 X 10~4

? 2 (5 = 0.1 dyne cm"

°C y °C y

250 66.63 350 56.22

260 65.61 360 55.14

270 64.59 370 54.07

280 63.57 380 52.98

290 62.53 390 51.89

300 61.49 400 50.80

310 60.45 410 49.70

320 59.40 420 48.59

330 58.34 430 47.48

340 57.28 440 46.36

Reference: 7 , [46].

Melting Point: [69],

Table 43. Sodium iodide, Nal

mp 662 °C

[Classification: Group A; for discussion see p. 64.]

7 = 433.7 — 0.793? + 0.437 x 10_3

?2 (s = 1.0 dyne cm" 1

°C y

760 83.4

770 82.2

780 81.0

790 80.0

800 79.0

810 78.1 820 77.3

830 76.6

840 75.9

850 75.4

860 74.9

Reference: 7 , [ 1 , 37, 46].

Melting Point: [69],

87
Table 44. Potassium iodide, KI

mp 685 °C

[Classification: Group B; for discussion see p. 64.]

y— 138.7 — 0.087t (5 = 0.2 dyne cm-1

)

°c y °C y °C y

700 77.8 770 71.7 840 65.6

710 76.9 780 70.8 850 64.8

720 76.1 790 70.0 860 63.9

730 75.2 800 69.1 870 63.0

740 74.3 810 68.2 880 62.1

750 73.5 820 67.4 890 61.3

760 72.6 830 66.5 900 60.4

Reference: y, [1, 46].

Melting Point: [69].

Table 45. Rubidium iodide, Rbl

mp 640 °C

[Classification: Group B; for discussion see p. 64.]

y = 140.2 — 0.103f + 0. 193 X 10~4

t

2 (s = 0.1 dyne cm-1 )

°C y °C y °C y

670 79.85 790 70.88 910 62.45

680 79.08 800 70.15 920 61.78

690 78.32 810 69.43 930 61.10

700 77.56 820 68.72 940 60.43

710 76.80 830 68.00 950 59.77

720 76.05 840 67.30 960 59.11

730 75.30 850 66.59 970 58.45

740 74.55 860 65.89 980 57.79

750 73.81 870 65.19 990 57.15

760 73.07 880 64.51 1000 56.50

770 72.33 890 63.82 1010 55.86

780 71.60 900 63.13 1020 55.22

Reference: 7 [46]

Melting Point: [69],

Table 46. Cesium iodide, Csl

mp 621 °C

[Classification: Group B; for discussion see p. 64.]

7 = 125.4 — 0.0946r + 0.219 x 10_4

r

2 (5 = 0.2 dyne cm-1 )

°C y °C y °C y °C y

650 73.16 750 66.77 850 60.81 950 55.30

660 72.50 760 66.15 860 60.24 960 54.77

670 71.85 770 65.54 870 59.67 970 54.24

680 71.19 780 64.94 880 59.11 980 53.73

690 70.55 790 64.33 890 58.55 990 53.21

700 69.91 800 63.74 900 57.99 1000 52.70

710 69.27 810 63.14 910 57.44 1010 52.19

720 68.64 820 62.55 920 56.90 1020 51.69

730 68.01 830 61.97 930 56.36 1030 51.19

740 67.39 840 61.39 940 55.83

Reference: 7 [46]

Melting Point: [69],

88
Table 47. Calcium iodide, CaL

mp 575 °C

[Classification: Group B; for discussion see p. 65.]

7 = 98.63 — 0.0173f (5=1.5 dyne cm-1

)

°c y °C y

800 84.79 930 82.54

810 84.62 940 82.37

820 84.44 950 82.20

830 84.27 960 82.02

840 84.10 970 81.85

850 83.93 980 81.68

860 83.75 990 81.50

870 83.58 1000 81.33

880 83.41 1010 81.16

890 83.23 1020 80.98

900 83.06 1030 80.81

910 82.89 1040 80.64

920 82.71 1050 80.47

Reference: y, [34].

Melting Point: [69].

Table 49. Barium iodide, Bal2 mp 740 °C

[Classification: Group B; for discussion see p. 65.]

y= 165.7 — 0.0420^ (5 = 0.4 dyne cm -1

)

°C y °C y

830 130.8 900 127.9

840 130.4 910 127.5

850 130.0 920 127.1

860 129.6 930 126.6

870 129.2 940 126.2

880 128.7 950 125.8

890 128.3 960 125.4

Reference: 7, [35] , Melting Point: [69].

Table 48. Strontium iodide, SrL

mp 515 °C

[Classification: Group B; for discussion see p. 65]

7= 114.6 + 0.0144r — 0.334 x 10~4

f

2 (5 = 0.9 dyne cm-1

)

°C y °C y °C y °C y

580 111.7 680 108.9 780 105.5 890 101.0

590 111.5 690 108.6 790 105.1 900 100.5

600 111.2 700 108.3 800 104.7 910 100.0

610 110.9 710 108.0 810 104.3 920 99.6

620 110.7 720 107.7 820 104.0 930 99.1

630 110.4 730 107.3 830 103.5 940 98.6

640 110.1 740 107.0 840 103.1 950 98.1

650 109.9 750 106.6 850 102.7 960 97.6

660 109.6 760 106.3 860 102.3 970 97.1

670 109.3 770 105.9 870 101.9 980 96.6

880 101.4 990 96.1

Reference: 7, [34].

Melting Point: [69].

89
TABLE 50. Boron trioxide, B2 03 mp 450 °C

[Classification: Group B; for discussion see p. 65.]

y — 47.57 + 0.0354J (5 = 0.04 dyne cm -1

)

°c 7 °C 7 °C 7

700 72.35 940 80.85 1180 89.34

720 73.06 960 81.55 1200 90.05

740 73.77 980 82.26 1220 90.76

760 74.47 1000 82.97 1240 91.47

780 75.18 1020 83.68 1260 92.17

800 75.89 1040 84.39 1280 92.88

820 76.60 1060 85.09 1300 93.59

840 77.30 1080 85.80 1320 94.30

860 78.01 1100 86.51 1340 95.01

880 78.72 1120 87.22 1360 95.71

900 79.43 1140 87.93 1380 96.42

920 80.14 1160 88.63 1400 97.13

Table 51. Aluminum oxide, lead oxide, andferrous oxide

Aluminum oxide, ALOn mp 2040 °C

[Classification: Group C; for discussion see p. 65.]

°C 7

2050 ±15 690.0

Reference: 7 , [30].

Melting Point: [69],

Lead oxide, PbO mp 886 °C

[Classification: Group C; for discussion see p. 65.]

°C 7

900 132.0

1000 134.8

Reference: y, [91]

Melting Point: [69].

Reference: y, [30, 33].

Melting Point: [69].

Ferrous oxide, FeO mp 1368 °C

[Classification: Group C; for discussion see p. 66.]

°C 7

1415-1423 585. (mean value)

Reference: y, [90, 87].

Melting Point: [69],

Table 52. Silicon dioxide, Si02 mp 1470 °C

[Classification: Group C; for discussion see p. 65.]

y = 251.7 + 0.031f (5 = 6.0 dyne cm -1

)

°C 7 °C 7 °C 7

1500 298.2 1610 301.6 1710 304.7

1510 298.5 1620 301.9 1720 305.0

1520 298.8 1630 302.2 1730 305.3

1530 299.1 1640 302.5 1740 305.6

1540 299.4 1650 302.9 1750 305.9

1550 299.8 1660 303.2 1760 306.3

1560 300.0 1670 303.5 1770 306.6

1570 300.3 1680 303.8 1780 306.9

1580 300.7 1690 304.1 1790 307.2

1590

1600

301.0

301.3

1700 304.4 1800 307.5

Reference: y, [30]

Melting Point: [69].

90
TABLE 53. Germanium dioxide, Ge02

mp 1116 °C

[Classification: Group C; for discussion see p. 65.

|

y = 185.6 + 0.056t (s = 5.0 dyne cm -1

)

°c y °C y

1200 252.8 1310 259.0

1210 253.4 1320 259.5

1220 253.9 1330 260.1

1230 254.5 1340 260.6

1240 255.0 1350 261.2

1250 255.6 1360 261.8

1260 256.2 1370 262.3

1270 256.7 1380 262.9

1280 257.3 1390 263.4

1290

1300

257.8

258.4

1400 264.0

Reference: y, [30]

.

Melting Point: [69].

Table 54. Phosphorus trioxide, P2O3

mp 23.8 °C

[Classification: Group B; for discussion see p. 66.]

y = 40.4 — 0.116r (s = 0.2 dyne cm -1)

°C y

30 37.0

40 35.8

50 34.7

60 33.5

70 32.3

80 31.2

90 30.0

100 28.9

no 27.7

Reference: 7, [5],

Melting Point: [69],

Table 55. Phosphorus pentoxide, P2O5

mp 569 C C

[Classification: Group C; for discussion see p. 66.] 7 = 62.1 —0.02 It (5= 1.8 dyne cm -1

)

°C y °C y

100 60.0 210 57.7 110 59.8 220 57.5

120 59.6 230 57.3

130 59.4 240 57.1 140 59.2 250 56.9

150 59.0 260 56.6

160 58.7 270 56.4

170 58.5 280 56.2

180 58.3 290 56.0

190 58.1 300 55.8

200 57.9

Reference: 7, [30]

.

Melting Point: [69].

Table 56. Thallium sulfide, T1>S

mp 448 °C

[Classification :Group B; for discussion see p. 66.]

7 = 231.4 — 0.0356t (s = 0.4 dyne cm -1

)

°C y °C y °C y

500 213.6 570 211.1 640 208.6

510 213.2 580 210.8 650 208.3

520 212.9 590 210.4 660 207.9

530 212.5 600 210.0 670 207.6

540 212.2 610 209.7 680 207.2

550 211.8 620 209.3 690 206.8

560 211.5 630 209.0 700 206.5

Reference: 7, [85].

Melting Point. [69],

335-493 0-69—7 91
Table 57. Lithium metaborate, LiB02

mp 845 °C

[Classification: Group B; for discussion see p. 66.]

y = 197.7 + 0.174? — 1.16 X 10 -4

?

2 (s=1.0 dyne cm- 1 )

°c 7 °C 7 °C y

880 261.0 1100 248.7 1320 225.3

900 260.3 1120 247.1 1340 222.6

920 259.6 1140 245.3 1360 219.8

940 258.8 1160 243.5 1380 216.9

960 257.8 1180 241.5 1400 213.9

980 256.8 1200 239.5 1420 210.9

1000 255.7 1220 237.3 1440 207.7

1020 254.5 1240 235.1 1460 204.5

1040 253.2 1260 232.8 1480 201.1

1060 251.8 1280 230.4 1500 197.7

1080 250.3 1300 227.9 1520 194.2

Reference: y, [46].

Melting Point: [69],

Table 58. Sodium metaborate, NaBO-2 mp 966 °C

[Classification: Group B; for discussion see p. 66.]

y = 359.6 — 0.163? ( 5 = 1.0 dyne cm-1)

°C 7 °C 7 °C 7

1020 193.3 1160 170.5 1300 147.7

1040 190.1 1180 167.3 1320 144.4

1060 186.8 1200 164.0 1340 141.2

1080 183.6 1220 160.7 1360 137.9

1100 180.3 1240 157.5 1380 134.7

1120 177.0 1260 154.2 1400 131.4

1140 173.8 1280 151.0 1420 128.1

Reference: y, [46].

Melting Point: [69],

TABLE 59. Potassium metaborate, KBO2 mp 947 °C

[Classification: Group B; for discussion see p. 66.]

y — 948.2 — 1.3998? + 5.727 X 10-4

?

2 (s = 0.6 dyne cm -1

)

°C 7 °C 7

990 123.8 1070 106.2

1000 121.2 1080 104.5

1010 118.7 1090 102.9

1020 116.3 1100 101.5

1030 114.1 1110 100.1

1040 111.9 1120 98.9

1050 109.9 1130 97.8

1060 108.0 1140 96.8

Reference: y, [46].

Melting Point: [69].

Table 60. Lithium carbonate, L^COs

mp 618 °C

[Classification: Group A; for discussion see p. 66.] y = 273. 5 — 0.0406? (5 = 0.5 dyne cm -1

)

°C 7

750 243.1

760 242.6

770 242.2

780 241.8

790 241.4

800 241.0

810 240.6

820 240.2

830 239.8

840 239.4

850 239.0

Reference: y, [49, 76].

Melting Point: [69].

92
Table 61. Sodium carbonate, Na2C0.3

mp 854 °C

[Classification: Group B; for discussion see p. 67.]

7 = 254.8 — 0.0502/ (5 = 0.1 dyne cm -1

)

°c y °C y

870 211.1 940 207.6

880 210.6 950 207.1

890 210.1 960 206.6

900 209.6 970 206.1

910 209.1 980 205.6

920 208.6 990 205.1

930 208.1 1000 204.6

1010 204.1

Reference: y, [49],

Melting Point: [69],

TABLE 62. Potassium carbonate, K2CO3

mp 896 °C

[Classification: Group B; for discussion see p. 67.]

7 = 283.2 — 0.183/ + 0.625 X 10 -4

/

2 (5 = 0.2 dyne cm -1

)

°C y

910 168.4

920 167.7

930 167.1 940 166.4

950 165.8

960 165.1

970 164.5

980 163.9

990 163.3

1000 162.7

1010 162.1

Table 63. Lithium nitrate, LiNOg

mp 254 °C

[Classification: Group B; for discussion see p. 67.]

7= 129.9 — 0.055/ (5 = 0.5 dyne cm 1 )

°C y °C y °C y

300 113.4 370 109.6 440 105.7

310 112.9 380 109.0 450 105.2

320 112.3 390 108.5 460 104.6

330 111.8 400 107.9 470 104.1 340 111.2 410 107.4 480 103.5

350 110.7 420 106.8 490 103.0

360 110.1 430 106.3 500 102.4

Reference: 7, [19, 26, 46],

Melting Point: [69].

Table 64. Sodium nitrate, NaNC>3

mp 310 °C

[Classification: Group A; for discussion see p. 67.] 7= 138.8 — 0.0613/ (5 = 0.3 dyne cm -1

)

°C y °C y °C y

320 119.2 420 113.1 520 106.9

330 118.6 430 112.4 530 106.3

340 118.0 440 111.8 540 105.7

350 117.4 450 111.2 550 105.1

360 116.7 460 110.6 560 104.5

370 116.1 470 110.0 570 103.9

380 115.5 480 109.4 580 103.3

390 114.9 490 108.8 590 102.6

400 114.3 500 108.2 600 102.0

410 113.7 510 107.5

Reference: 7, [1, 18, 19, 26, 41, 46].

Melting Point: [69].

Reference: 7, [49].

Melting Point: [69].

93
Table 65. Potassium nitrate, KNO3

mp 337 °C

[Classification: Group A; for discussion see p. 67.]

y = 136.5 — 0.0750? (5 = 0.1 dyne cm-1

)

°c 7 °C 7

340 111.0 420 105.0

350 110.3 430 104.3

360 109.5 440 103.5

370 108.8 450 102.8

380 108.0 460 102.0

390 107.3 470 101.3

400 106.5 480 100.5

410 105.8 490 99.8

500 99.0

Reference: y, [1, 18, 19, 26, 46, 48].

Melting Point: [69],

Table 66. Rubidium nitrate, RbNOs

mp 316 °C

[Classification: Group B; for discussion see p. 68.]

y= 134.3 — 0.083? (5 = 0.4 dyne cm -1

)

°C 7 °C 7 °C 7

330 106.9 430 98.6 530 90.3

340 106.1 440 97.8 540 89.5

350 105.3 450 96.9 550 88.7

360 104.4 460 96.1 560 87.8

370 103.6 470 95.3 570 87.0

380 102.8 480 94.5 580 86.2

390 101.9 490 93.6 590 85.3

400 101.1 500 92.8 600 84.5

410 100.3 510 92.0

420 99.4 520 91.1

Reference: y, [26, 46].

Melting Point: [69],

Table 67. Cesium nitrate, CsNOs

mp 414 °C

[Classification: Group B; for discussion see p. 68.]

y — 122. 1 — 0.074? (5 = 0.4 dyne cm' 1 )

°C 7 °C 7

420 91.0 520 83.6

430 90.3 530 82.9

440 89.5 540 82.1 450 88.8 550 81.4

460 88.1 560 80.7

470 87.3 570 79.9

480 86.6 580 79.2

490 85.8 590 78.4

500 85.1 600 77.7 510 84.4

Reference: y, [19, 26, 46].

Melting Point: [69].

Table 68. Silver nitrate, AgNC>3 mp 210 °C

[Classification: Group B; for discussion see p. 68.]

y= 162.5 — 0.0613? (5 = 0.7 dyne cm -1

)

°C 7 °C 7

220 149.0 290 144.7

230 148.4 300 144.1

240 147.8 310 143.5

250 147.2 320 142.9

260 146.6 330 142.3

280 146.0 340 141.7

350 141.1

Reference: y, [1, 18, 19, 26],

Melting Point: [69],

94
Table 69. Thallium nitrate, TINO3

mp 207 °C

[Classification: Group B; for discussion see p. 69.]

7=110.9 — 0.078/ (5 = 0.4 dyne cm -1

)

°c y °C y °C y

210 94.5 300 87.5 390 80.5

220 93.7 310 86.7 400 79.7

230 93.0 320 85.9 410 78.9

240 92.2 330 85.2 420 78.1

250 91.4 340 84.4 430 77.4

260 90.6 350 83.6 440 76.6

270 89.8 360 82.8 450 75.8

280 89.1 370 82.0 460 75.0

290 88.3 380 81.3

Reference: 7, [19, 46].

Melting point: [69],

Table 70. Ammonium nitrate, NH4 N03 mp 169.6 °C

[Classification: Group C; for discussion see p. 69.]

7= 119.7 — 0.105/ (5 = 0.5 dyne cm-1

)

°C y

170 101.9

180 100.8

190 99.8

200 98.7

210 97.7

220 96.6

Reference: 7, [19, 74].

Melting Point: [69],

Table 71. Calcium nitrate, strontium nitrate, and

barium nitrate

Calcium nitrate, Ca(N03 )2 * mp 551 °C

[Classification: Group C; for discussion see p. 69.] 7= 101.5 ±0.5 at 560 °C

Strontium nitrate, Sr(N03)2 * mp 605 °C

[Classification: Group C; for discussion see p. 69.] 7= 128.4 ±0.5 at 615 °C

Barium nitrate, Ba(N03 )2 * mp 595 °C

[Classification: Group C; for discussion see p. 69.] 7=143.7 — 0.015/ (5 = 0.6 dyne cm-1

)

°C y

600 134.7

610 134.6

620 134.4

630 134.3

640 134.1

650 134.0

660 133.8

*Reference: 7, [19].

Melting Point: [69],

Table 72. Sodium nitrite, NaNO»

mp 281 °C

[Classification: Group B; for discussion see p. 70.]

7=131.4 — 0.0378/ (5 = 0.4 dyne cm -1

)

°C y °C y °C y

280 120.8 360 117.8 440 114.8

290 120.4 370 117.4 450 114.4

300 120.0 380 117.0 460 114.0

310 119.7 390 116.7 470 113.6

320 119.3 400 116.3 480 113.2

330 118.9 410 115.9 490 112.9

340 118.6 420 115.5 500 112.6

350 118.2 430 115.2

Reference: 7, [ 1 , 19, 23].

Melting Point: [69],

95
TABLE 73. Potassium nitrite, KNO2 mp 419 °C

{Classification: Group B; for discussion see p. 70.]

y = 134.6 — 0.0623* ( 5 = 0.3 dyne cm-1

)

°c 7

450 106.6

460 105.9

470 105.3

480 104.7

490 104.0

500 103.5

Reference: y, [19].

Melting Point: [69].

Table 74. Lithium silicate, Li2 Si 03

mp 1188 °C

[Classification: Group B; for discussion see p. 70.]

y = 819.9 — 0.572* + 1.73 X 10 -4

* 2 (s = 1.0 dyne cm -1

)

°C 7 °C 7 °C 7

1250 375.2 1370 361.0 1490 351.7

1260 373.8 1380 360.0 1500 351.2

1270 372.5 1390 359.1 1510 350.6

1280 371.2 1400 358.2 1520 350.2

1290 369.9 1410 357.3 1530 349.7

1300 368.7 1420 356.5 1540 349.3

1310 367.5 1430 355.7 1550 348.9

1320 366.3 1440 355.0 1560 348.6

1330 365.2 1450 354.2 1570 348.3

1340 364.1 1460 353.6 1580 348.0

1350 363.0 1470 352.9 1590 347.8

1360 362.0 1480 352.3 1600 347.6

Reference: y, [46].

Melting Point. [69].

Table 75. Magnesium metasilicate, MgSi03 mp 1525 °C

[Classification: Group C; for discussion see p. 70.] y= 224.1 + 0.098*

°C 7

1540 375.1

1550 376.0

1560 377.0

1570 378.0

1580 379.0

1590 380.0

1600 381.0

1610 381.9

1620 382.9

Reference: y, [58].

Melting Point: [69].

Table 76. Calcium metasilicate, CaSiOs

mp 1530 °C

[Classification: Group C; for discussion see p. 70.] y = 367 + 0.021t

°C 7

1530 399.2

1540 399.4

1550 399.6

1560 399.8

1570 400.0

1580 400.2

1590 400.4

1600 400.6

1610 400.8

1620 401.1

Reference: y, [58],

Melting Point: [69].

96
Table 77. Manganese metasilicate, MnSi03 mp 1272 °C

[Classification: Group C; for discussion see p. 70.] y = 280 + 0.086r

Table 79. Lithium metaphosphate, LiP03 mp 675 ± 4 °C

[Classification: Group B; for discussion see p. 71.]

7 = 206.1 — 0. 0222t (s = 1.0 dyne cm' 1 )

°c y

1450 404.7

1460 405.5

1470 406.4

1480 407.3

1490 408.1

1500 409.0

1510 409.8

1520 410.7

1530 411.6

1540 412.2

1550 413.3

1560 414.1

1570 415.0

1580 415.9

Reference: y, [58].

Melting Point: [69].

Table 78. Manganese orthosilicate, Mn2 Si 04

mp 1290 °C

[Classification: Group C; for discussion see p. 70.] 7 = 468.4 + 0.015*

°C y

1410 489.6

1430 489.9

1450 490.2

1470 490.5

1490 490.8

1510 491.1

1530 491.4

1550 491.7

1570 492.0

1590 492.3

Reference: y, [58],

Melting Point: [69].

°C y °C y °C y

750 189.5 860 187.0 970 184.6

760 189.2 870 186.8 980 184.3

770 189.0 880 186.6 990 184.1

780 188.8 890 186.3 1000 183.9

790 188.6 900 186.1 1010 183.7

800 188.3 910 185.9 1020 183.5

810 188.1 920 185.7 1030 183.2

820 187.9 930 185.5 1040 183.0

830 187.7 940 185.2 1050 182.8

840 187.5 950 185.0 1060 182.6

850 187.2 960 184.8 1070 182.4

Reference: 7 , [9].

Melting Point: [69],

Table 80. Sodium metaphosphate, NaP03 mp 625 °C

[Classification: Group A; for discussion see p. 71.]

7 = 217.8 — 0.0398t (5 = 0.2 dyne cm -1

)

* °C y °C y °C y

660 191.6 770 187.2 880 182.7

670 191.2 780 186.8 890 182.3

680 190.8 790 186.4 900 181.9

690 190.4 800 185.9 910 181.5

700 190.0 810 185.5 920 181.1

710 189.6 820 185.1 930 180.7

720 189.2 830 184.7 940 180.2

730 188.8 840 184.3 950 179.8

740 188.4 850 183.9 960 179.4

750 188.0 860 183.5 970 179.0

760 187.6 870 183.1 980 178.6

Reference: 7 , [9, 27, 28, 46, 88 ]. Melting Point: [69],

97
Table 81. Potassium metaphosphate, KPO3

mp 817 °C

[Classification: Group A; for discussion see p. 71.] y = 193.2 — 0.0556? (5 = 0.3 dyne cm -1

)

Table 83. Calcium metaphosphate, CafPOsfi

mp 975 °C

[Classification: Group B; for discussion see p. 72.]

7 = 240.6 — 0.0108? (5=0.8 dyne cm-1)

Reference: y, [27,46,9],

Melting Point: [69],

Reference: y, [9, 27].

Melting Point: [69].

Table 82. Cesium metaphosphate, CsPO,3

mp 724 ± 3 °C

[Classification: Group C; for discussion see p. 72.] y = 153.3 — 0.0487? (5 = 0.4 dyne cm -1

)

°c y °C y °C y

740 117.3 850 111.9 950 107.0

750 116.8 860 111.4 960 106.5

760 116.3 870 110.9 970 106.0

770 115.8 880 110.4 980 105.6

780 115.3 890 109.9 990 105.1 790 114.8 900 109.5 1000 104.6

800 114.3 910 109.0 1010 104.1

810 113.8 920 108.5 1020 103.6

820 113.3 930 108.0 1030 103.1

830

840

112.9

112.4

940 107.5 1040 102.7

TABLE 84. Strontium metaphosphate, SrfPO.-Ai

mp 1010±5 °C

[Classification: Group C; for discussion see p. 72.] y = 233.7 — 0.00527? (5 = 0.5 dyne cm-1

)

°C y

1030 228.27

1040 228.22

1050 228.17

1060 228.11

1070 228.06

1080 228.01

Reference: y, [9],

Melting Point: [69],

Reference: y, [9].

Melting Point: [69],

98
Table 85. Barium metaphosphate, Ba(P0,{>2

rn p 868 ± 5 °C

[Classification: Group C; for discussion see p. 72.) y = 239.9 — 0.0177£ (5 = 0.5 dyne cm-1

)

Table 87. Sodium sulfate, NaiSO^

mp 884 °C

[Classification: Group B; for discussion see p. 73.]

y = 476.5 — 0.532t + 2.43 X 10~^£ 2 (5=1.1 dyne cm-1

)

Reference: y, [9].

Melting Point: [69],

Reference: y, [46].

Melting Point: [69]

Table 86. Lithium sulfate, Li:>S04

mp 859 °C

[Classification: Group A; for discussion see p. 72.] 7 = 282.6 — 0.0672t (s = 0.1 dyne cm-1

)

°c y °C y °C y

860 224.8 950 218.8 1040 212.7

870 224.1 960 218.1 1050 212.0

880 223.5 970 217.4 1060 211.4

890 222.8 980 216.7 1070 210.7

900 222.1 990 216.1 1080 210.0

910 221.5 1000 215.4 1090 209.4

920 220.8 1010 214.7 1100 208.7

930 220.1 1020 214.1

940 219.4 1030 213.4

Table 88. Potassium sulfate , K2SO4

mp 1069 °C

[Classification: Group A; for discussion see p. 73.] 7 = 224.3 — 0.0765t (5 = 0.1 dyne cm-1

)

°C y

1080 141.7

1090 140.9

1100 140.2

1110 139.4

1120 138.6

Reference: 7, [6, 13, 46].

Melting Point: [69],

Reference: 7, [4, 46].

Melting Point: [69].

99
Table 89. Rubidium sulfate, Rb2 S04

mp 1074 °C

[Classification: Group B; for discussion see p. 73.]

y = 286.1 — 0.207f + 0.596 X 10_4

t 2 (5= 0.3 dyne cm-1

)

°c y °C y °C y °C y °C y

1080 132.1 1180 124.8 1280 118.8 1380 113.9 1480 110.3

1090 131.3 1190 124.2 1290 118.3 1390 113.5 1490 110.0

1100 130.5 1200 123.5 1300 117.7 1400 113.1 1500 109.7

1110 129.8 1210 122.9 1310 117.2 1410 112.7 1510 109.4

1120 129.0 1220 122.3 1320 116.7 1420 112.3 1520 109.2

1130 128.3 1230 121.7 1330 116.2 1430 112.0 1530 108.9

1140 127.6 1240 121.1 1340 115.7 1440 111.6 1540 108.7

1150 126.9 1250 120.5 1350 115.3 1450 111.3 1550 108.4

1160 126.2 1260 119.9 1360 114.8 1460 110.9

1170 125.5 1270 119.3 1370 114.4 1470 110.6

Reference: 7, [46]

Melting Point: [69],

Table 90. Cesium sulfate, CS2 SO4 mp 1019 °C

[Classification: Group B; for discussion see p. 73.]

7 — 244.3 — 0.179t + 0.483 X 10_4

f

2 (s = 0.4 dyne cm-1

)

°C y °C y °C y °C y °C y

1040 110.4 1140 103.0 1240 96.6 1340 91.2 1440 86.7

1050 109.6 1150 102.3 1250 96.0 1350 90.7 1450 86.3

1060 108.8 1160 101.7 1260 95.4 1360 90.2 1460 85.9

1070 108.1 1170 101.0 1270 94.9 1370 89.7 1470 85.5

1080 107.3 1180 100.3 1280 94.3 1380 89.3 1480 85.2

1090 106.6 1190 99.7 1290 93.8 1390 88.8 1490 84.8

1100 105.8 1200 99.1 1300 93.2 1400 88.4 1500 84.5

1110 105.1 1210 98.4 1310 92.7 1410 87.9 1510 84.1

1120 104.4 1220 97.8 1320 92.2 1420 87.5 1520 83.8

1130 103.7 1230 97.2 1330 91.7 1430 87.1 1530 83.5

Reference: 7, [ 46] . Melting Point: [69].

100
Table 91. Sodium molybdate

,

NaaMoCb

mp 687 °C

[Classification: Group B; for discussion see p. 74.]

y = 309.5 — 0.172f + 0.498 X 10-4

£ 2

( 5 =0.6 dyne cm-')

°c y °C y °C y °C y

700 213.5 830 201.1 960 190.3 1090 181.2

710 213.5 840 200.2 970 189.5 1100 180.6

720 211.5 850 199.3 980 188.8 1110 179.9

730 210.5 860 198.4 990 188.0 1120 179.3

740 209.5 870 197.6 1000 187.3 1130 178.7

750 208.5 880 196.7 1010 186.6 1140 178.1

760 207.5 890 195.9 1020 185.9 1150 177.6

770 206.6 900 195.0 1030 185.2 1160 177.0

780 205.6 910 194.2 1040 184.5 1170 176.4

790 204.7 920 193.4 1050 183.8 1180 175.9

800 203.8 930 192.6 1060 183.1 1190 175.3

810 202.9 940 191.8 1070 182.5 1200 174.8

820 202.0 950 191.0 1080 181.8 1210 174.3

Reference: 7, [46].

Melting Point: [69],

Table 92. Potassium molybdate, K2M0O4

mp 926 °C

[Classification: Group B; for discussion see p. 74.]

7= 182.3 — 0.0158J — 0.199 X 10-4

i

2 (5 = 0.4 dyne cm-1

)

Table 93. Lead molybdate, PbMoC>4

mp 1065 °C

[Classification: Group B; for discussion see p. 74.]

7 = 236.0 — 0.064^ (s = 0.9 dyne cm-1)

Reference: 7, [ 24] . Melting Point: [69].

Reference: 7, [46]

.

Melting Point: [69].

101
Table 94. Bismuth molybdate. Bi-dMoChh

mp 643 °C

[Classification: Group B; for discussion see p. 74.

|

y = — 207.2 + 1.1 lOt — 0.834 X 10 _3C (s = 0.6 dyne cm"1 )

°c y

680 162.0

690 161.6

700 161.1

710 160.5

720 159.7

730 158.7

740 157.5

750 156.2

760 154.7

Reference: y, [24]

Melting Point: [24].

Table 95. Sodium tungstate , Na^WC^

mp 698 °C

[Classification: Group B; for discussion see p. 74.]

y = 248. 1 — 0.0602? — 0.0414 X 10~4C (s = 0.6 dyne cm-1

)

°C y °C y

750 200.6 1200 169.9

800 197.3 1250 166.4

850 193.9 1300 162.8

900 190.6 1350 159.3

950 187.2 1400 155.7

1000 183.8 1450 152.1

1050 180.3 1500 148.5

1100 176.9 1550 144.8

1150 173.4 1600 141.2

Reference: y, [46].

Melting Point: [69].

TABLE 96. Potassium tungstate, K2WO4

mp 930 °C

[Classification: Group B; for discussion see p. 74.] y = 283.6 — 0.160t + 0.283 X 10 -4C (5= 0.6 dyne cm'1 )

°C y °C y °C y

940 158.2 1140 138.0 1340 120.0

960 156.1 1160 136.1 1360 118.3

980 154.0 1180 134.2 1380 116.7

1000 151.9 1200 132.4 1400 115.1

1020 149.8 1220 130.5 1420 113.5

1040 147.8 1240 128.7 1440 111.9

1060 145.8 1260 126.9 1460 110.3

1080 143.8 1280 125.2 1480 108.8

1100 141.8 1300 123.4 1500 107.3

1120 139.9 1320 121.7 1520 105.8

Reference: y, [46]

Melting Point: [69],

TABLE 97. Potassium thiocyanate and potassium chlorate

Potassium thiocyanate, KCNS* mp 175 °C

[Classification: Group C; for discussion see p. 74.] y = 339.5 — 1.36f (fresh melt) (s = 0.5 dyne cm-1

) y = 126.0 — 0.14t (aged melt) (5 = 0.5 dyne cm-1

)

°C y

(fresh melt)

y

(aged melt)

175 101.5 101.5

185 88.9 100.1

195 98.7

205 97.3

Potassium chlorate, KClO.i* mp 368 °C

[Classification: Group C: for discussion see p. 74.] y = 228.0 — 0.40f (5 = 0.5 dyne cm-1

)

^Reference: y, [23]

Melting Point: [23].

102
Table 98. Potassium dichromate, K2 Cr2 C>7 mp 398 °C

[Classification: Group B; for discussion see p. 74.] 7 = 236.2 — 0.27? (5=0.5 dyne cm'1 )

Table 99. Lithium chlorate, LiClO.i

mp 127.8 °C

[Classification: Group B; for discussion see p. 75.]

7 = 96.71—0.0692? (5 = 0.1 dyne cm-1

)

Reference: y, [23, 46],

Melting Point: [69],

Reference: 7, [68].

Melting Point: [68].

Table 100. Sodium chlorate, NaClO.s

mp 255 °C

[Classification: Group B; for discussion see p. 75.]

7=110.27 — 0.0738? (5=0.4 dyne cm-1

)

°c y

260 91.08

270 90.34

280 89.61

290 88.87

Reference: 7, [21].

Melting Point: [69],

103
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8. References

[References marked with asterisks have data for molten salt mixtures.]

*[1] Bloom, H., Davis, F. G., and James, D. W., Trans. Faraday

Soc., 56, 1179 (1960).

[2] Ellis, R. B., and Wilcox, W. S., Prog. Rep. U.S.A.E.C., Contract No. At—(40—1)—2073, TplO-7622, pp. 128—36

(1962).

[3] Sokolova, O. K., Izv. Akas. Nauk. S.S.S.R., Met.; Gorn. Delo 4, 59 (1963).

*[4] Semenchenko, K., and Shikhobalova, L. P., J. Phys. Chem.

(U.S.S.R.), 21, 707 (1947).

[5] Schenck, R., Mihr, F., and Banthien, H., Ber. der Deut. Chem. Ges. 39, 1506 (1906); International Critical Tables

(E. W. Washburn, Ed.), (McGraw-Hill Book Company,

Inc., New York, 1926).

*[6] Neithamer, R. W., and Peake, J. S., J. Chem. Eng. Data,

6, 197 (1961).

*[7] Lantratov, M. F., Zhur. Prik. Khim., 34, L249 (1961).

[8] Sokolova, I. D., and Sokolova, V. A., Rus. J. Phys. Chem.,

34, 944 (1960).

[9] Sokolova, I. D., and Voskresenskaya, N. K., Zhur. Neorg.

Khim. 8 , 2625 (1963).

[10] Barzakovskii, V. P., Zhur. Phiz. Khim., 13, 1117 (1940).

[11] Ellis, R. B., Smith, J. E., and Baker, E. B., J. Phys. Chem.,

62, 766 (1958).

*[12] Peake, J. S., and Bothwell, M. R., J. Am. Chem. Soc., 76,

2656 (1954).

*[13] Sokolova, I. D., and Voskresenskaya, N. K., Russ. J. Phys.

Chem., 36, 502 (1962).

*[14] Boardman, N. K., Palmer, A. R., and Heymann, E. Trans. Faraday. Soc., 51, 277 (1955).

*[15] Ellis, R. B., Smith, J. E., Wilcox, W. S., and Crook, E. H.,

J. Phys. Chem., 65, 1186 (1961).

[16] Greenwood, N. N., and Worrall, I. J., J. Chem. Soc., 1680

(1958).

[17] Nijjhar, R. S., M. S. Thesis, University of Bradford, U.K.

(1967).

*[18] Dahl, J. L., and Duke, F. R., J. Phys. Chem., 62, 1142

(1958).

[19] Addison, C. C., and Coldrey, J. M., J. Chem. Soc., 468

(1961).

[20] Semenchenko, K., and Shikhobalova, L. P., J. Phys. Chem.

(U.S.S.R.) 21, 613 (1947); (C.A. 41, 67780-

*[21] Campbell, A. N., and van Der Kouwe, E. T., Can. J. Chem.

46, 1279 (1968).

[22] NBS Technical News Bulletin, October, 1963.

[23] Frame, J. P., Rhodes, E., and Ubbelohde, A. R., Trans. Faraday Soc., 55, 2039 (1959).

*[24] Morris, K. B., McNair, N., and Koops, G., J. Chem. Eng.

Data, 7, No. 2, 244 (1962).

[25] Motylewski S., Z. anorg. u. allgem. Chem. 38,410(1904).

*[26] Bertozzi, G., and Sternheim, G., J. Phys. Chem., 68 , 2908

(1964). [27a] Williams, D. J., Bradbury, B. T., and Maddocks, W. R.,

J. Soc. Glass Technol., 43, 3087 (1959). [27b] Bradbury, B. T., and Maddocks, W. R., J. Soc. Glass Technol. 42 , 325T (1959).

*[28] Callis, C. F., Van Wazer, J. R., and Metcalf, J. S., J. Am.

Chem. Soc., 11, 1468 (1955).

*[29] Lehman, D. S., Ph. D. Thesis, Indiana University, U.S.A.

(1959).

[30] Kingery, W. D., J. Am. Ceram. Soc., 42 (1), 6 (1959).

*[31] Dahl, J. L., and Duke, F. R., J. Phys. Chem., 62, 1498

(1958).

[31a] Dahl, J. L., and Duke, F. R., Prog. Rep. U.S.A.E.C. Contract No. W-7405-Eng.-82 (1957).

*[32] Bloom, H., and Burrows, B. W., Proceedings of the 1st Australian Electrochemistry Conference 882 (1963).

*[33] Shartsis, L., and Canga, R., J. Res. NBS 43, No. 3, 221

(1949), RP2023.

[34] Ellis, R. B., Prog. Rep. U.S.A.E.C., Contract No. AT-

(40— 1)—2073, II (1958).

*[35] Ellis, R. B., Prog. Rep. U.S.A.E.C., Contract No. AT-

(40-l)-2073, III (1958).

*[36J Ellis, R. B., Prog. Rep. U.S.A.E.C., Contract No. AT-

(40-l)-2073 (1959).

*[37] Ellis, R. B., Prog. Rep. U.S.A.E.C., Contract No. AT-

(40— 1)—2073 (1961).

[38] Ellis, R. B., Prog. Rep. U.S.A.E.C., Contract No. AT-

(40-l)-2073 (1962).

[39] Ellis, R. B., Prog. Rep. U.S.A.E.C., Contract No. AT-

(40-l)-2073 (1963).

*[40] Reding, J. D., J. Chem. Eng. Data, 11 (2), 239 (1966).

*[41] Semenchenko, K., and Shikhobalova, L. P., Zhur. Fiz. Khim., 21,613 (1947).

[42] Greenwood, N. N., and Wade,K., J. Chem. Soc. 1663 (1958).

[43] Greenwood, N. N., and Wade, K., J. Chem. Soc. 1671 (1958).

[44] Greenwood, N. N., and Wade, K., J. Inorg. and Nucl. Chem. 3, 349 (1957).

[45] Bertozzi, G., J. Phys. Chem. 69, 2606 (1965).

[46] Jaeger, F. M., Z. anorg. u. allgem. Chem., 101, 1 (1917).

[47] Rogers, M. T., and Garver, E. E., J. Phys. Chem. 62, 952

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3037 (1966).

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9. Compound Index

Page

AgBr 59, 86, 105 AgCl 59, 81, 104 Agl 59 AgNO, 68, 69, 94, 107

AlCl, 62, 84, 105 Al.Oi 54, 55, 65, 90, 105

B,03 BaBr>

BaCl,

BaL

Ba(NO:i )2 .- Ba(P03 ),... BiBr:) Bid........ Bi2 (Mo04 )3

54, 65, 90, 105

64, 65, 86, 105

60, 82, 104

61, 89, 105

69, 70, 95, 107

71, 99, 107

62, 87, 105

62, 84, 105

....74, 102, 108

CaBr, 61, 86, 105 CaCL, 60, 82, 104

Cal, 65, 89, 105

Ca(NO-i)-, 69, 95, 107 Ca(POs), 55, 72, 98, 107 CaSiO, 70, 71, 96, 107 CdBr2 61, 87, 105 CdCl, 61, 83, 104 CsBr 63, 85, 105 CsCl 58, 59, 81, 104 CsF 55, 79, 104 Csl 64, 88, 105 CsN03 68, 94, 107 CsPO:t 71, 98, 107 Cs2 SO, 73, 100, 107 CuCl 55, 59, 81, 104 Cu,S 55, 59, 81, 106

FeO 55, 66, 90, 106

GaCL

Gad, • C5 H5 N

Gad, • C5 H,oNH.

Gad, 2C-TI l oNH

GeO52, 62, 84, 105

62, 84, 105

62, 84, 105

62, 84, 105

54, 65, 91, 106

HgBr2 55, 61, 83, 105 HgCL 55, 61, 83, 104

KBO, 66, 92, 106

KBr 63, 85, 105 KC1 58, 80, 104 KCIO, 74, 102, 108 KCNS 74, 102, 108

Page

K2 C03 67, 93, 106 K2 Cr2 0- 74, 75, 103, 108 KF 57, 78, 104 KI 64, 88, 105 K2 Mo04 74. 101, 108 KN02 70, 96, 107 KNO:, 67, 68, 94, 106 KPO.j 71, 98, 107 K2 S04 73, 99, 107 K2 W04 74, 102, 108

LiBO,..

Lid

LiC103 . Li2 COs . LiF

LiNCL..

LiPOs .. Li,S04 .. Li>SiO:! . MgCl2 .. MgSiO:,

MnSiO:) MnSi04

66, 92, 106

55, 80, 104

....75, 103, 104

66, 92, 106

55, 78, 104

67, 93, 106

71, 97, 107

.72, 73, 99, 107

70, 96. 107

.55, 59, 81, 104

70, 71, 96, 107

70, 71, 97, 107

.70, 71, 97, 107

Na: ,AlF«

NaBO,..

NaBr.... NaCL...

NaClO-i.

57, 79, 104

66, 92, 106

62, 85, 105

...57, 58, 80, 104

75, 102, 103, 108 Na2 C03 67, 93, 106 NaF 56. 57, 78, 104 Nal 64, 87, 105 Na,Mo04 74, 101, 108 NaNO, 70, 95, 107

NaNO.-, 67, 93, 106 NaP03 52, 71, 97, 107 Na2 S04 73, 99, 107 Na,W04 74, 102, 108 NH4 NO:i 69, 95, 107 P.O:! 66, 91, 106 P2 05 52, 54, 66, 91, 106 PbCl2 61, 83, 105 PbMo04 74, 101, 108 PbO 55, 65, 90, 106 RbBr 63, 85, 105 RbCl 58, 80, 104 RbF 55, 78, 104 Rbl 64. 88, 105

110
Page

RbN03 68, 94, 106 Rb2 S04 73, 100, 107

Si02 54, 65, 90, 106 SnCl2 61, 83, 104 SrBr2 64, 65, 86, 105

SrCl, 65, 82, 104

Srl2 65, 89,405

Sr(NO.,)2 69, 70, 95, 107 Sr(P03 ) 2 71, 98, 107

Page

ThF4 57, 79, 104 TINOi 69, 95, 107

T12 S 66, 91, 106

UF4 57, 79, 104 UF(; 52, 55, 57, 79, 104

ZnBr, 60, 87, 105 ZnCl2 51, 52, 53, 60, 82, 104

111

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