National Institute of Standards & Technology

Certificate of Analysis
Standard Reference Material 674b
X-Ray Powder Diffraction Intensity Set(Quantitative Powder Diffraction Standard)This Standard Reference Material (SRM) consists of four oxide powders (ZnO, TiO2, Cr2O3, and CeO2), intended
primarily for use as internal standards for quantitative X-ray diffraction analysis. These four oxides offer a range of
linear attenuations for Cu-Kα radiation: 279 cm–1 (ZnO, wurtzite structure), 536 cm–1 (TiO2, rutile structure),
912 cm–1 (Cr2O3, corundum structure), and 2203 cm–1 (CeO2, fluorite structure) that allow the user to nominally matchthe standard to the unknown in order to minimize the effects of microabsorption. A unit of SRM 674b consists ofapproximately 10 g of each powder, bottled in an argon atmosphere.
Material Description: The powders consist of fine-grained high-purity equi-axial grains that are not in an aggregatedstate. The isometric form of the grains effectively eliminates preferred orientation effects in these powders. The
de-aggregated state of these materials ensures the homogeneity of test mixtures prepared by conventional methods.
An analysis of the lattice parameters and phase fractions determined from X-ray powder diffraction data collectedfrom mixtures of SRM 674b and SRM 676 [1] indicated that the SRM material was homogeneous with respect todiffraction properties.
Certified Values: A NIST certified value is a value for which NIST has the highest confidence in its accuracy in thatall known or suspected sources of bias have been investigated or taken into account. The measurands are the certified
values for the crystalline phase purity of the four materials and the lattice parameters that are provided in Tables 1
and 3, respectively. Metrological traceability is to the SI units for the derived unit of mass fraction (expressed as
milligrams per kilogram), and for length (expressed as nanometers); for crystalline phase purity and lattice parameters,
respectively. The certified values and uncertainties were calculated according to the method described in the ISO/JCGM
Guide [2].
Information Values: An information value is considered to be a value that will be of interest and use to the SRM
user, but insufficient information is available to adequately assess the uncertainty associated with the value, or it is avalue derived from a limited number of analyses. Information values cannot be used to establish metrologicaltraceability. Information values for the relative intensity values, I/Ic values [3] (for a complete discussion see
reference 4) and microstructural parameters are provided in Tables 4-6. The particle size data, as determined by laser
scattering, are given Table 7.
Expiration of Certification: The certification of SRM 674b is valid indefinitely, within the uncertainty specified,provided the SRM is handled and stored in accordance with the instructions given in this certificate (see “Instructionsfor Handling, Storage, and Use”). Accordingly, periodic recalibration or recertification of this SRM is not required.
The certification is nullified if the SRM is damaged, contaminated, or otherwise modified.
Maintenance of SRM Certification: NIST will monitor this SRM over the period of its certification. If substantive
technical changes occur that affect the certification, NIST will notify the purchaser. Registration (see attached sheet
or register online) will facilitate notification.
Technical direction and overall coordination on the certification of this SRM were provided by J.P. Cline of the NIST
Materials Measurement Science Division.
John A. Small, Chief
Materials Measurement Science Division
Gaithersburg, MD 20899
Certificate Issue Date: 15 November 2017

Steven J. Choquette, Director
Office of Reference Materials

Certificate Revision History on Last Page

SRM 674b

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Material preparation, measurements, and data analysis leading to the certification of this SRM were performed by
R.S. Winburn of Minot State University (Minot, ND), J.P. Cline, D. Black, M.H. Mendenhall and A. Henins of the
NIST Materials Measurement Science Division, and R.B. Von Dreele of Argonne National Laboratory (Argonne, IL).
Statistical analysis was provided by J.J. Filliben and I. Aviles of the NIST Statistical Engineering Division.
Support aspects involved in the issuance of this SRM were coordinated through the NIST Office of Reference Materials.
SOURCE, PREPARATION, AND ANALYSIS( 1)0F

Materials: The ZnO and TiO2 powders of SRM 674b were obtained from Alfa Aesar (Ward Hill, MA) and Cr2O3 andCeO2 powders were obtained from Cerac Inc. (Milwaukee, WI).
Phase Purity: The consideration of a long-count-time X-ray powder diffraction pattern may indicate that the sample
is a high-purity powder, i.e., no peaks from impurity phases and a background that is consistent with contributions of
air scatter from the incident beam and thermal diffuse scatter from the sample. However, the surface region of any
crystalline material will not diffract as the bulk due to relaxation of the crystal structure and inclusion of surface
reaction products. While this surface layer may only be on the order of a few crystallographic units in thickness, in a
finely divided solid it can easily account for several percent of the total mass. The characterization of “phase purity”
or “amorphous content” discussed herein is not in the context of a mechanically separable impurity phase, but it is a
microstructural characteristic innate to the chemistry and the production history of the SRM feedstock.
Certification Method: The oxide powders of this SRM were certified with respect to the mass fraction of material
that exhibits Bragg scattering in correspondence to their crystal structure, or phase purity, and lattice parameters. The
certification procedure utilized Quantitative Rietveld Analyses (QRA) [5] (for a complete discussion of the Rietveld
method, see references 6 and 7) of neutron time-of-flight (TOF) diffraction measurements in conjunction with the useof SRM 676 as the internal standard. This procedure referenced the phase purity of SRM 674b against that of
SRM 676. The basis of the method rests on an analysis of the discrepancy between the results of powder diffraction
experiments, which measure the mass of material exhibiting Bragg diffraction, relative to weighing operations, which
include all components.
The QRA of laboratory, divergent beam X-ray powder diffraction (XRPD) data displayed a systematic bias of lessthan 2 %; however, these results were as precise as those determined from the TOF data. Therefore, the certified
phase composition was determined from the TOF data while the homogeneity of the SRM material was verified with
Rietveld analyses of XRPD data. It should be noted that the mechanism inducing this bias is not operative in Reference
Intensity Ratio (RIR) based methods [8] (for a complete discussion of RIR methods, see reference 4). The emission
spectrum of Cu Kα radiation of the XRPD experiment is used as the basis for constructing the diffraction profiles
within the fundamental parameters approach (FPA) [9] method for diffraction line profile analysis. The emission
spectrum provides the linkage of the certified lattice parameter values to the fundamental unit of length, as defined by
the International System of Units (SI) [10]. With the use of the FPA, diffraction profiles are modeled as a convolutionof functions that describe the wavelength spectrum, the contributions from the diffraction optics, and the sample
contributions resulting from microstructural features. Analysis of data from a divergent-beam instrument requires
knowledge of both the diffraction angle and the effective source-sample-detector distance. Two additional models
are therefore included in the FPA analyses to account for the effect of the sample height and attenuation. Certification
data were analyzed in the context of both Type A uncertainties, assigned by statistical analysis, and Type B
uncertainties, based on knowledge of the nature of errors in the measurements, to result in the establishment of robust
uncertainties for the certified values.
Certification Procedure: Ten bottles were selected from the population in accordance to a stratified random protocol.
Samples taken from two bottles were combined and admixed with SRM 676 at the 50 % level to yield a total of fivesamples for TOF neutron diffraction analysis. TOF data were obtained on the High Intensity Powder
Diffractometer (HIPD) at the Manuel Lujan, Jr., Neutron Scattering Center (LANSCE) (Los Alamos, NM). The
samples were contained in 9.5 mm diameter by 50 mm long vanadium cans during the analysis. Each sample was
exposed to the neutron beam for 1.3 h with the LANSCE source operating at 70 µA proton beam current. Data used
for this certification were obtained from detector banks positioned at ± 153° 2θ covering a d-space range of 0.05 nm
to 0.48 nm. The run order was randomized on an informal basis. Rietveld refinements using the General Structure
Analysis System (GSAS) [11] of the phases in these samples included: scale factors, lattice parameters of theSRM 674b materials (those of SRM 676 were fixed at the certified values) a profile shape function term representing
Lorentzian peak broadening [12], atomic positional and thermal parameters, a term for the diffractometer (DIFC), an(1) Certain commercial instruments, materials, or processes are identified in this certificate to adequately specify theexperimental procedure. Such identification does not imply recommendation or endorsement by the National Institute of Standards
and Technology, nor does it imply that the instruments, materials, or processes identified are necessarily the best available for the
purpose.

SRM 674b

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absorption correction term, and six terms of a background function describing the effects of thermal diffuse andincoherent scattering. The amorphous phase content was determined from the mass fraction ratio determined fromthe diffraction experiment relative to that of the weighing operation, with the latter ratio being corrected for the known
phase purity of SRM 676. The certified phase purity of these materials, expressed as a mass fraction is given in
Table l.
Table l. Certified Phase Purity Mass Fractions
Crystalline Component
ZnO
TiO2
Cr2O3
CeO2

Phase Purity (%)
95.28
89.47
95.91
91.36

±
±
±
±

0.64
0.62
0.60
0.55

The interval defined by the certified value and its uncertainty represents an expanded uncertainty using k = t, where t
is the appropriate 2-sided 95 % confidence interval coefficient, in the absence of systematic error. The uncertainty
reported does not include that of the phase purity determination of the standard used for this certification, SRM 676.
Two X-ray diffractometers were used for collection of certification data. The first was a Siemens D5000
diffractometer equipped with a sample spinner, graphite post monochromator and scintillation detector. Data fromthis machine were used to verify the homogeneity of the powders, determine the relative intensities and I/Ic values.
The second was a NIST-built machine used for the certification of lattice parameters and determination of
microstructural data. A full discussion of this machine can be found in reference 13. It was configured in a manner
analogous to the D5000. The instruments were aligned and calibrated using SRMs 660a [14], for the D5000, and660b [15,16] for the NIST machine, in a manner described in reference 13. The data collected for certification of thelattice parameters were analyzed using the FPA method with Rietveld analyses as implemented in TOPAS [17].
Mendenhall et al. [18] verified that TOPAS operated in accordance with published models for the FPA. The analysis
used the Cu Kα1/Kα2 emission spectrum, including a satellite component, as characterized by G. Hölzer et al. and Maskil& Deutsch [19,20]. The intensities and positions of the Cu Kα2 line, the satellite line and the “tube tails” [21] wererefined. Constraints were applied to positions and intensities of the Kα21 and Kα22 lines to preserve the overall shapeas per Hölzer. A Soller slit value, constrained to be identical for both the incident and diffracted beam, using the “full”
axial divergence model [22], was refined. This procedure allowed for determination of parameters specific to the
instrument profile function (IPF) [13] and were fixed in subsequent analyses of SRM 674b materials.
Diffraction data for homogeneity testing were collected on two specimens removed from each of the ten
aforementioned bottles. These specimens also had SRM 676 admixed with them in a 50:50 mass ratio. The scan
range was from 20° to 155° 2θ with a step width of 0.02° and a count time of 3.5 s/step. The divergence slit width
was 0.85°; a 2.3° incident Soller slit and a 0.05° receiving slit were used. These data were analyzed with Rietveld
method via GSAS. The refined parameters included the scale factors, a background represented by a fifth order
Chebyshev polynomial with a 1/x term, the lattice parameters of the SRM 674b materials, specimen displacement,
attenuation, size and strain (when relevant) terms and structural parameters. Additional data were collected from threephase pure specimens of each of the SRM materials for determination of the relative intensity values. Both the I/Ic
and relative intensity values were determined by profile fitting of all peaks within the angular range of 20° to 70° 2θ
using the FPA method. The refined diffraction intensities used for determination of the I/Ic values were corrected forthe known amorphous contents of the two phases, i.e., the material of SRM 674b and the alumina of SRM 676.
Data for certification of lattice parameters and determination of microstructural data were collected from 5 randomly
selected bottles of the four SRM 674b materials. The NIST machine utilized essentially the same slit dimensions as
were used on the D5000. The data were collected in three 2θ ranges with the step widths and count times optimized
for each material and region with respect to profile breadth and diffraction intensity. Total scan time for each sample
was approximately 10 hours. The analysis of the IPF included a refinement of the breadths of emission spectrum toaccount for the effects of the graphite monochromator [13]. The analysis was performed as per the homogeneity
testing except that the crystallite size broadening was modeled with a log-normal size distribution of sphericalcrystallites using the Scardi and Leoni formalism [23]. The average of the five values for μ and σ obtained from useof this model were used to obtain the reported crystallite size data. The analyses of the TiO2 and Cr2O3 materials
included Lorentzian breadth term that varied as tan θ that is interpreted as microstrain, to determine the reported ε0values, where (ε0)2 is the mean squared strain. Again, the reported value is the average of the five obtained from therefinements. The refined lattice parameters were adjusted using the coefficient of thermal expansion values found inTouloukian et al. [24] to values in correspondence with 22.5 °C. Statistical analysis provided the Type A uncertainties
reported in Table 2. However, the components of uncertainty that were evaluated by Type B methods must also betaken into account, and these are roughly one order of magnitude larger than those that were evaluated using statisticalmethods. Data were considered primarily in the context of the uniformity in lattice parameter as a function of 2θ
SRM 674b

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angle [25]; this, in turn, would reflect the functionality of the FPA model. This approach was applied to data from
SRM 660b used to calibrate the machine. This consideration leads to an assignment of Type A + B uncertainty of
0.000 030 0 nm to the a and c lattice parameters; the certified values are shown in Table 3.
INSTRUCTIONS FOR HANDLING, STORAGE, AND USE
Storage: SRM 674b was bottled under an argon atmosphere to protect against humidity. Although there have been
no long-term stability studies on this SRM, the oxides of which it is composed are known to be a stable in the ambientconditions of a typical laboratory. It is, therefore, believed that this SRM is stable after exposure to atmosphere. Itis, nonetheless, recommended that the unused portion of the powder be stored in a tightly capped container such as
the original bottle or in a manner to afford similar or greater protection against humidity.
Information Values and Uncertainties: NIST information values are considered to be of interest to the SRM user,
but are not certified because the measurements are not traceable to the SI, or only a limited number of analyses were
performed which disallowed imparting plausible uncertainties to the measured values. The informational values
determined from the aforementioned analyses of XRPD data are presented in Tables 4 thorough 6. The particle size
distributions, determined from a disc centrifuge analyzer, are given in Table 7. The interval defined by a value andits uncertainty is a 95 % confidence interval for the true value of the mean in the absence of systematic error.

Table 2. Lattice Parameters Values and Type A Uncertainties for SRM 674b Powders
Component

Lattice Parameter a(nm)

Uncertainty Type A(k = 2)

ZnO
TiO2
Cr2O3
CeO2

0.324 986 50
0.459 394 52
0.495 858 64
0.541 152 60± 0.000 000 48± 0.000 002 30± 0.000 003 02± 0.000 000 30

Lattice Parameter c Uncertainty Type A(nm)(k = 2)0.520 673 64
0.295 890 90
1.359 650 66± 0.000 002 92± 0.000 001 23± 0.000 011 92

Table 3. Certified Lattice Parameters of SRM 674b
Component

Lattice Parameter a(nm)

Uncertainty
Type A + B(k = 2)

Lattice Parameter c(nm)

Uncertainty
Type A + B(k = 2)

ZnO
TiO2
Cr2O3
CeO2

0.324 987
0.459 395
0.495 859
0.541 153

± 0.000 030 0± 0.000 030 0± 0.000 030 0± 0.000 030 00.520 674
0.295 891
1.359 651

± 0.000 030 0± 0.000 030 0± 0.000 030 0

Table 4. Information I/Ic Values for SRM 674b
Component
ZnO
TiO2
Cr2O3
CeO2

SRM 674b

I/Ic
4.95
3.44
1.97
12.36

±
±
±
±

0.01
0.01
0.02
0.09

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Table 5. Information Relative Intensity Values of SRM 674b
ZnO
hkl

Angle

100
002
101
102
110
103
200
112
201

31.76
34.41
36.25
47.53
56.59
62.85
66.37
67.94
69.08

TiO2
Rel I (%)

61.30 ±
37.24 ±
100.0
22.29 ±
37.72 ±
30.28 ±
5.25 ±
27.13 ±
14.12 ±

2.34
2.10---0.66
1.44
1.14
0.24
0.12
0.32

hkl

Angle

110
101
200
111
210
211
220
002
310
301
112

27.45
36.09
39.20
41.25
44.05
54.32
56.63
62.76
64.05
69.00
69.80

Cr2O3
hkl

Angle

012
104
110
006
113
202
024
116
122
214
300
1 0 10

24.52
33.62
36.22
39.77
41.50
44.22
50.24
54.86
58.42
63.48
65.13
72.95

Rel I (%)
100.0
37.70
5.96
18.70
7.46
55.14
17.48
6.94
8.03
19.41
8.96

±
±
±
±
±
±
±
±
±
±

---1.50
0.12
0.48
0.25
1.58
0.31
0.40
0.21
0.62
0.58

CeO2
Rel I (%)

66.71 ±
100.0
81.27 ±
7.36 ±
31.64 ±
5.24 ±
39.64 ±
96.42 ±
8.17 ±
31.06 ±
39.31 ±
20.88 ±

1.71---4.78
0.93
0.60
0.25
1.10
0.64
0.74
1.55
1.43
1.53

hkl

Angle

111
200
220
311
222
400

28.61
33.14
47.54
56.39
59.14
69.46

Rel I (%)
100.0
27.21 ±
54.21 ±
43.58 ±
8.29 ±
8.03 ±---0.46
0.56
0.60
0.38
0.25

Table 6. Information Microstructural Data for SRM 674b
Component
10 %
ZnO
TiO2
Cr2O3
CeO2
(1)

5.3
0.8
73.4
11.4

Microstrain, (ε0) (1)Crystallite Size, Mass Percent Less Than
(nm)
25 %
50 %
75 %
8.8
1.6
93.5
18.6

15.5
3.6
122.4
31.9

90 %

27.3
8.0
160.3
54.6

45.4
16.7
204.2
88.6

*
0.000170.00010**: None detected.
Table 7. Information Particle Size Data for SRM 674b Determined Using a Disk Centrifuge Analyzer
Mass Percent Less
Than (µm)
10 %
16 %
50 %
84 %
90 %

SRM 674b

Components
ZnO

TiO2

Cr2O3

CeO2

0.22
0.28
0.58
1.15
1.55

0.41
0.55
0.93
1.38
1.66

0.34
0.38
0.56
1.05
1.45

0.53
0.65
1.13
1.91
2.18
Page 5 of 7

REFERENCES[1]

SRM 676; Alumina Internal Standard for Quantitative Analysis by X-ray Powder Diffraction; National Instituteof Standards and Technology; U.S. Department of Commerce: Gaithersburg, MD (2005).
[2]
JCGM 100:2008; Guide to the Expression of Uncertainty in Measurement; (GUM 1995 with Minor
Corrections),
Joint
Committee
for
Guidesin
Metrology (JCGM) (2008);
availableat
http://www.bipm.org/utils/common/documents/jcgm/JCGM_100_2008_E.pdf (accessed Nov 2017); see also
Taylor, B.N.; Kuyatt, C.E.; Guidelines for Evaluating and Expressing the Uncertainty of NIST Measurement
Results; NIST Technical Note 1297; U.S. Government Printing Office: Washington, DC (1994); available at
http://physics.nist.gov/Pubs/contents.html (accessed Nov 2017).
[3]
Visser, J.W.; deWolff, P.M.; Absolute Intensities; Report No. 641.109; Technisch Physische Dienst: Delft,
The Netherlands (1964).
[4]
Snyder, R.L.; The Use of Reference Intensity Ratios in X-ray Quantitative Analysis; Powder Diff. J., Vol. 7, No. 4,
pp. 186−192 (1992).
[5]
Rietveld, H.M.; Line Profiles of Neutron Powder Diffraction Peaks for Structure Refinement; Acta Crytsallogr.,Vol. 22, pp. 151−152 (1967); and Rietveld, H.M.; A Profile Refinement Method for Nuclear and Magnetic
Structures; J. Appl. Crystallogr., Vol. 2, pp. 65−71 (1969).
[6]
The Rietveld Method; Young, R.A., Ed.; Oxford University Press (1993).
[7]
Modern Powder Diffraction; Bish, D.L.; Post, J.E., Eds.; Rev. Mineral., Vol. 20 (1989).
[8]
Chung, F.H.; Quantitative Interpretation of X-ray Diffraction Patterns. I. Matrix-Flushing Method of Multi
Component Analysis; J. Appl. Crystallogr., Vol. 7, pp. 519–525 (1974); and Chung, F.H.; Quantitative
Interpretation of X-ray Diffraction Patterns. II. Adiabatic Principle of X-ray Diffraction Analysis of Mixtures;
J. Appl. Crystallogr., Vol. 7, pp. 526–531 (1974).
[9]
Cheary, R.W.; Coelho, A.A.; A Fundamental Parameters Approach to X-ray Line-Profile Fitting; J. Appl.
Crystallogr., Vol. 25, pp. 109−121 (1992).
[10] BIPM; International System of Units (SI); Bureau International des Poids et Mesures; 8th ed.; Sèvres,France (2006); available at http://www.bipm.org/utils/common/pdf/si_brochure_8_en.pdf (accessed Nov 2017).
[11] Larson, A.C.; Von Dreele, R.B.; General Structure Analysis System (GSAS); Report LAUR 86-748; Los Alamos
National Laboratory: Los Alamos, NM (2003).
[12] Von Dreele, R.B.; Jorgensen, J.D.; Windsor, C.G.; Rietveld Refinement with Spallation Neutron Powder
Diffraction Data; J. Appl. Crystallogr., Vol. 15, pp. 581−589 (1982).
[13] Cline, J.P.; Mendenhall, M.H.; Black, D.; Windover, D; Henins, A.; The Optics and Alignment of the Divergent
Beam Laboratory X-ray Powder Diffractometer and its Calibration using NIST Standard Reference Materials;
J. Res. Natl. Inst. Stand. Technol, Vol. 120, pp. 173–222 (2015).
[14] SRM 660a; Lanthanum Hexaboride Powder Line Position and Line Shape Standard for Powder Diffraction;
National
InstituteofStandards
andTechnology;
U.S.
Department
ofCommerce:
Gaithersburg, MD (13 September 2000).
[15] SRM 660b; Line Position and Line Shape Standard for Powder Diffraction; National Institute of Standards
and Technology; U.S. Department of Commerce: Gaithersburg, MD (29 April 2010).
[16] Black, D.; Windover, D.; Henins, A.; Filliben, J.J.; Cline, J.P.; Certification of Standard Reference Material
660B; Powder Diffr., Vol. 26 (2), pp. 155–158 (2011).
[17] Bruker AXS. Topas v5, a component of DIFFRAC.SUITE (2014); available athttps://www.bruker.com/products/x-ray-diffraction-and-elemental-analysis/x-ray-diffraction/xrdsoftware/overview/topas.html (accessed Nov 2017).
[18] Mendenhall, M.H.; Mullen, K.; Cline, J.P.; An Implementation of the Fundamental Parameters Approachfor Analysis of X-ray Powder Diffraction Line Profiles; J. Res. Natl. Inst. Stand. Technol., Vol. 120,
pp. 223–251 (2015).
[19] Hölzer, G.; Fritsch, M.; Deutsch, M.; Härtwig, J.; Förster, E.; Kα1,2 and Kβ1,3 X-ray Emission Lines of the 3dTransition Metals; Phys. Rev. A, Vol. 56, No. 6, pp. 4554−4568 (1997).
[20] Maskil, M.; Deutsch, M.; X-Ray Kα Satellites of Copper; Phys. Rev. A, Vol. 38, pp. 3467–3472 (1988).
[21] Bergmann, J.; Kleeberg, R.; Haase, A.; Breidenstein, B.; Advanced Fundamental Parameters Model for Improved
Profile Analysis; In Proceedings of the 5th European Conference on Residual Stresses: Delft-Noordwijkerhout,
The Netherlands, September 29−30 (1999); Böttger, A.J.; Delhez, R.; Mittemeijer, E.J., Eds.; Trans Tech
Publications; Materials Science Forum, Vol. 347–349, pp. 303−308 (2000).
[22] Cheary, R.W.; Coelho, A.A.; Axial Divergence in a Conventional X-ray Powder Diffractometer I, Theoretical
Foundations; J. Appl. Crystallogr., Vol. 31, pp. 851−861 (1998); and Cheary, R.W.; Coelho, A.A.; Axial
Divergence in a Conventional X-ray Powder Diffractometer II, Implementation and Comparison with Experiment;
J. Appl. Crystallogr., Vol. 31, pp. 862−868 (1998).

SRM 674b

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[23]
[24]
[25]

Scardi, P.; Leoni, M.; Diffraction Line Profiles from Polydisperse Crystalline Systems; Acta Cryst. A,
Vol. 57(5), pp. 604–613 (2001).
Touloukian, Y.S.; Kirby, R.K.; Taylor, R.E.; Lee, T.Y.R.; Thermophysical Properties of Matter Volume 13.
Thermal Expansion – Nonmetallic Solids; IFI/Plenum (1977).
Cline, J.P, Black, D., Gil, D., Henins, A. and D., Windover; The Application of the Fundamental Parameters
Approach as Implemented in TOPAS to Divergent Beam Powder Diffraction Data; Materials Science Forum
Vol. 651, pp. 201-219 (2010).

Certificate Revision History: 15 November 2017 (Addition of certified lattice parameters; editorial changes); 13 March 2012 (Corrected ZnO
c lattice parameter and uncertainty; corrected the ZnO and TiO2 relative intensity values; editorial changes); 21 November 2011 (Updated title;
editorial changes); 27 September 2011 (Updated title; editorial changes); 29 January 2007 (Correction of datum for the angle at hkl222 in Table 5
for CeO2; Restatement of datum applicable to the receiving slit used in the scan range; editorial changes); 21 September 2005 (Original certificatedate).

Users of this SRM should ensure that the Certificate of Analysis in their possession is current. This can beaccomplished by contacting the SRM Program:
telephone (301) 975-2200; fax (301) 948-3730; e-mailsrminfo@nist.gov; or via the Internet at http://www.nist.gov/srm.
SRM 674b

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