Physics and Chemistry of Minerals (2018) 45:511–521
https://doi.org/10.1007/s00269-017-0938-6

ORIGINAL PAPER

Martinandresite, ­Ba2(Al4Si12O32)·10H2O, a new zeolite from Wasenalp,
Switzerland
Nikita V. Chukanov1 · Natalia V. Zubkova2 · Nicolas Meisser3 · Stefan Ansermet3 · Stefan Weiss4 · Igor V. Pekov2 ·Dmitriy I. Belakovskiy5 · Svetlana A. Vozchikova1 · Sergey N. Britvin6 · Dmitry Yu. Pushcharovsky2
Received: 14 October 2017 / Accepted: 10 December 2017 / Published online: 16 December 2017
© Springer-Verlag GmbH Germany, part of Springer Nature 2017

Abstract
The new zeolite martinandresite, ideally B­ a2(Al4Si12O32)·10H2O, was discovered in the armenite locality of Wasenalp near
the Isenwegg peak, Ganter valley, Simplon region, Switzerland. The associated minerals are armenite, quartz, dickite, andchlorite. Martinandresite forms tan-coloured blocky crystals up to 8 × 5 × 3.5 mm, their aggregates up to 6 cm across, as wellas cruciform twins up to 3.5 mm. The major form is {010}; the subordinate forms are {100} and {001}. Indistinct cleavage
is observed, presumably on (010) and in a direction across (010). The Mohs’ hardness is 4½. Density measured by flotationin heavy liquids is 2.482(5) g/cm3. Density calculated using the empirical formula is equal to 2.495 g/cm3. Martinandresite
is optically biaxial, negative, α = 1.500(2), β = 1.512(2), γ = 1.515(2) (λ = 589 nm). 2V (meas.) = 55(10)°. The IR spectrum isgiven. The chemical composition of martinandresite is (wt%; electron microprobe, ­H2O determined by the modified Penfield
method): ­Na2O 0.37, K­ 2O 0.12, BaO 21.55, A­ l2O3 15.03, S­ iO2 49.86, H­ 2O 12.57, total 99.50. The empirical formula basedon 16 atoms Si + Al pfu is ­Na0.17K0.04Ba2.00(Al4.19Si11.81O32)H19.85O9.93. The crystal structure was determined using singlecrystal X-ray diffraction data. The new mineral is orthorhombic, space group Pmmn, with a = 9.4640(5), b = 14.2288(6),c = 6.9940(4) Å, V = 941.82(8) Å3 and Z = 1. The crystal structure of martinandresite is unique and is based on the Al–Si–O
tetrahedral framework containing four-, six- and eight-membered rings of tetrahedra. Si and Al are disordered between thetwo independent tetrahedral sites. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 6.98 (74)(001), 6.26 (83) (011), 5.61 (100) (101), 3.933 (60) (220, 031), 3.191 (50) (112), 3.170 (62) (041), 3.005 (79) (231, 141).
Martinandresite is named after Martin Andres (b. 1965), the discoverer of the armenite locality of Wasenalp.
Keywords New mineral · Martinandresite · Harmotome · Zeolite group · Crystal structure · IR spectroscopy · Wasenalp ·Switzerland

Introduction

Electronic supplementary material The online version of thisarticle (https://doi.org/10.1007/s00269-017-0938-6) contains
supplementary material, which is available to authorized users.
* Nikita V. Chukanov
chukanov@icp.ac.ru
1

Institute of Problems of Chemical Physics, Russian Academyof Sciences, Chernogolovka, Moscow Region 142432,
Russia2

Faculty of Geology, Moscow State University,
Vorobievy Gory, Moscow 119991, Russia

3

Musée cantonal de géologie, Quartier UNIL, Dorigny,
Bâtiment Anthropole, 1015 Lausanne, Switzerland

The interest in zeolites goes beyond the scope of mineralogy,
because these solids not only occur naturally but are also
produced industrially on a large scale and are used as ion
exchangers, sorbents, catalysts and catalyst carriers. Each
4

Christian Weise Verlag, Ortlerstrasse 8, 81373 Munich,Germany

5Fersman Mineralogical Museum of Russian Academyof Sciences, Leninskiy Prospekt 18‑2, Moscow 119071,
Russia6

Department of Crystallography, Institute of Earth Sciences,Saint Petersburg State University, Universitetskaya Nab. 7/9,
199034 St., Petersburg, Russia

13Vol.:(0123456789)

512

discovery of a zeolite mineral belonging to a novel structural
type is of strong interest as a possible prototype of a material
with useful properties.
The new zeolite-group mineral martinandresite(Cyrillic: мартинандресит) with the idealized formula­Ba2(Al4Si12O32)·10H2O was discovered at the armenite
locality of Wasenalp near the Isenwegg peak, Ganter valley,
Simplon region, Switzerland (for the locality see: Hetherington 2001; Andres 2009; Weiss 2016). This area is also
the type locality of barium mica ganterite (Graeser et al.
2003; Graeser and Hetherington 2004). The geographicalcoordinates of Wasenalp are 46°16′6″N, 8°5′9″E.
Zoisite-, celsian- and armenite-bearing gneisses of Wasenalp contain up to 15 wt% Ba and are cut by steep open veins(Alpine clefts) trending NNW–SSE. Within these rocks,
late-stage hydrothermal fluids created a series of free-grownminerals, including clear quartz (rock crystal), calcite, brown
dravite and clinozoisite, whitish due to the clear armenite(Weiss 2016), and martinandresite.
The new mineral is intimately associated with armenite,
quartz, dickite, and chlorite. Some crystals are milky white
due to fine inclusions of dickite crystals. Fluid inclusions
studies of quartz and armenite showed (Hetherington 2001)
that these veins opened at a lithostatic pressure of ca. 3 kbar
at temperatures of 420–450 °C. Clear crystals of quartz andarmenite grew at 280–300 °C and 2 kbar. Similar late-stage
conditions might have prevailed during the crystallizationof martinandresite.
Martinandresite is named after the Swiss mineral collector and amateur mineralogist Martin Andres (b. 1965), thediscoverer of the armenite vein locality of Wasenalp. Martin
Andres has collected samples of the new mineral. In June
2016, he generously provided a sample of this mineral toone of the authors (SW). Martin Andres is also the author ofseveral popular publications on the minerals of Switzerland.
The mineral and its name have been approved by the IMA
Commission on New Minerals, Nomenclature and Classification (IMA no. 2017-038). The type material (a part of theholotype specimen) is deposited in the Geological Museumof Lausanne, Switzerland; the catalogue number is MGL
093284.

Physics and Chemistry of Minerals (2018) 45:511–521

bands corresponding to vibrations of C–O bonds in the IR
spectrum.
To obtain an IR absorption spectrum, martinandresite
powder was mixed with anhydrous KBr, pelletized, and analyzed using an ALPHA FTIR spectrometer (Bruker Optics)
at a resolution of 4 cm−1. 16 scans were collected. The IR
spectrum of an analogous pellet of pure KBr was used as areference.
Powder X-ray diffraction data were obtained using a
Rigaku R-AXIS Rapid II single-crystal diffractometerequipped with cylindrical image plate detector using the
Debye–Scherrer geometry (d = 127.4 mm). A CoKα radiation was used.
Single-crystal XRD studies of martinandresite were carried out using an Xcalibur S diffractometer equipped with a
CCD detector. A full sphere of three-dimensional data wascollected. Data reduction was performed using CrysAlisPro Version 1.171.37.35 (Agilent Technologies 2014). The
data were corrected for the Lorentz factor and polarization
effects.

Results
General appearance and physical properties
Martinandresite forms aggregates up to 6 cm across consisting of 6–8 mm-sized blocky and rounded tan crystals,
autoepitaxially covered by milk-white, cross-twinned
plates up to 3.5 mm (Figs. 1, 2). Blocky crystals up to
8 × 5 × 3.5 mm are observed (Fig. 2). These plates may form
scaly to lamellar aggregates to 7 mm, visually resembling
baryte and overgrowing blocky crystals (Fig. 1). More perfect platy crystals reach a maximum size of 5 × 3 × 0.7 mm.
Three pinacoids are definitely observed: {010} (the major

Experimental methods
Five chemical analyses were carried out using an Oxford
INCA Wave 700 electron microprobe (WDS mode, 20 kV,
600 pA, 300 nm beam diameter). ­H2O was determinedby the Alimarin method [the Penfield method was modified for small samples and involving selective sorption of­H2O on Mg(ClO4)2 from gaseous products obtained byheating the mineral at 1080 °C in oxygen at 1 atm]. ­CO2
was not analysed because of the absence of absorption

13

Fig. 1  Aggregates of platy to lamellar martinandresite crystals. Field
width 3 cm

Physics and Chemistry of Minerals (2018) 45:511–521

513

using the empirical formula and unit-cell parameters wereobtained from single-crystal X-ray diffraction (XRD) data.

Optical properties
Under the microscope, martinandresite is nonpleochroic, colourless. It is optically biaxial, negative,
α = 1.500(2), β = 1.512(2), γ = 1.515(2) (λ = 589 nm). 2V(meas.) = 55(10)°, 2V (calc.) = 53°. Dispersion of the optical axes is weak, r < v.
The mineral is non-fluorescent under both long- andshort-wave UV radiation.
Fig. 2  Fragment of the surface of a martinandresite blocky crystal
showing epitaxial overgrowth of platy crystals with two cleavages.
SEM photo: C. Rewitzer

form), {100} and {001}. Non-indexed faces are also present
on the crystals.
Martinandresite is transparent to translucent. The colour is white to tan, locally light green due to microscopic
chlorite inclusions. White colour may be due to dickite
inclusions (Fig. 3). The streak is white. The lustre is vitreous to porcelaneous. Macroscopically, two directionsof indistinct cleavage are observed, presumably on (010)
and in a direction across (010) (Fig. 2). No cleavage isobserved for small particles under the optical microscope.
The fracture is uneven. Parting has not been observed. The
Mohs’ hardness is 4½. Density measured by flotation inheavy liquids (mixtures of bromoform with benzene) is
2.482(5) g/cm3. A density of 2.495 g/cm3 was calculated

Infrared absorption spectroscopy
Absorption bands in the IR spectrum of martinandresite(Fig. 4) and their assignments are ­(cm−1; s—strong band,
w—weak band, sh—shoulder): 3625, 3570sh, 3260sh(O–H stretching vibrations of H
­ 2 O molecules), 1638

Fig. 4  Powder IR spectrum of (a) martinandresite and (b) harmotome­Ba1.90Na0.88K0.16(Al4.84Si11.16O32)·nH2O from Zlatolist, Eastern Rhodopes, Bulgaria

Table 1  Chemical composition (in wt%) of martinandresite

Fig. 3  Pure martinandresite (1) and martinandresite with inclusionsof dickite (2) and armenite (3). Polished section, BSE image. Field
width 0.6 mm

Constituent Averagecontent

Range

Standard Probe standard
deviation

Na2O
K 2O
BaO
Al2O3
SiO2
H2O
Total

0.29–0.47
0.00–0.22
21.13–22.08
14.72–15.34
49.53–50.18

0.06
0.06
0.43
0.23
0.29

0.37
0.12
21.55
15.03
49.86
12.57 ± 0.15
99.50

AlbiteOrthoclase
BaSO4
Albite
SiO2

13

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Physics and Chemistry of Minerals (2018) 45:511–521

Table 2  Powder X-ray diffraction data of martinandresite
Iobs

dobs (Å)

Icalc*

dcalc** (Å)

hkl

44
74
83
100
7
41
8
3
33
60
22
20
6
2
9
1
50
62
12
33
79
23
4
49
24
45
22
20
3
6
2
10
7
17
6
17
17
6
3
3
8
5
3
10
10
9
5
10
13
7

7.86
6.98
6.26
5.61
5.22
4.975
4.723
4.402
4.232
3.933
3.773
3.620
3.552
3.491
3.391
3.272
3.191
3.170
3.132
3.077
3.005
2.974
2.873
2.816
2.723
2.664
2.628
2.617
2.537
2.492
2.460
2.414
2.366
2.302
2.261
2.236
2.212
2.185
2.142
2.121
2.096
2.042
2.027
2.004
1.958
1.921
1.890
1.829
1.807
1.778

33
70
76
100
7
36
6
2
27
48, 4
22
19
5
2
8
1
44
43
8
29
24, 6021
4
41, 6, 6
23
50
7, 8
23
3
7
1
6, 6
1, 5
17, 1
7
1, 5, 6, 12
6, 10, 8
7
1, 2
2
10, 2, 3
62
12, 4
2, 2, 2, 11
10, 2
1, 8
8, 7
4, 1, 10, 3, 4, 4
12

7.880
6.994
6.277
5.625
5.231
4.988
4.732
4.412
4.240
3.940, 3.925
3.779
3.626
3.557
3.497
3.396
3.280
3.196
3.171
3.138
3.080
3.021, 3.006
2.979
2.876
2.819, 2.815, 2.812
2.725
2.666
2.636, 2.634
2.615
2.539
2.494
2.459
2.419, 2.411
2.371, 3.666
2.303, 2.301
2.264
2.246, 2.245, 2.236, 2.236
2.215, 2.214, 2.206
2.185
2.150, 2.138
2.120
2.100, 2.092, 2.091
2.043
2.026
2.006, 2.000
1.970, 1.963, 1.960, 1.956
1.922, 1.914
1.896, 1.889
1.829, 1.827
1.813, 1.813, 1.809, 1.804, 1.803, 1.803
1.779

110
001
011
101
111
021
200
121
130
220, 031
211
131
040
002
012
102
112
041
022
310
231, 141122
301
311, 032, 202
150
321051, 241
222
151
042
331
232, 142
060, 400
251, 013
103
061, 420, 341, 113023, 411, 242
161
152, 421
260
332, 033, 203133
431
223, 252
440, 062, 402, 342
162, 233
441, 422
361, 501
323, 262, 352, 271, 053, 243
080

13

Physics and Chemistry of Minerals (2018) 45:511–521

515

Table 2  (continued)
Iobs

dobs (Å)

Icalc*

dcalc** (Å)

hkl

6
2
3
2
6
11
4
6
8
5
5
5
6
1
2
4
1
4
6
3
2
2
2
3
3
4
1
4
3
3
1
3
2
2
1

1.759
1.723
1.709
1.696
1.674
1.662
1.641
1.626
1.577
1.567
1.541
1.512
1.507
1.491
1.473
1.466
1.448
1.424
1.405
1.395
1.386
1.374
1.362
1.355
1.337
1.332
1.302
1.276
1.257
1.245
1.229
1.222
1.215
1.205
1.198

4, 2, 4
1, 2
1, 3
3
5, 6
10, 8, 1, 6
4, 2
2, 2, 6, 2
9, 3
7, 2
3, 5, 2, 3
5, 3
5, 3
1
2, 2
2, 4
3
7, 3, 214, 3
3, 2, 2, 3
5
2, 4
2, 4
5, 3
2
10, 2, 2
1, 2, 25, 2, 6, 2, 6, 5
1, 1, 2, 7
1, 1, 6, 2
4
4
5
3, 1, 14

1.761, 1.758, 1.757
1.728, 1.724
1.716, 1.709
1.696
1.675, 1.671
1.663, 1.661, 1.660, 1.653
1.641, 1.640
1.629, 1.629, 1.625, 1.621
1.577, 1.576
1.565, 1.559
1.550, 1.542, 1.539, 1.535
1.512, 1.510
1.506, 1.503
1.490
1.471, 1.469
1.464, 1.462
1.447
1.424, 1.421, 1.417
1.405, 1.404
1.399, 1.399, 1.394, 1.392
1.385
1.376, 1.373
1.363, 1.362
1.355, 1.354
1.347
1.333, 1.328, 1.326
1.308, 1.300, 1.296
1.285, 1.278, 1.275, 1.274, 1.274, 1.270
1.261, 1.260, 1.256, 1.255
1.247, 1.244, 1.243, 1.242
1.228
1.221
1.214
1.205, 1.203, 1.203
1.197451, 530, 072
172, 081
442, 370
181
460, 124
063, 403, 371, 512
034, 204
214, 461, 541, 522
600, 550
353, 190
234, 091, 601, 372
173, 462
471, 282
054
363, 503
631, 513
561
192, 254, 382
344, 533
414, 183, 0.10.1, 164391
632, 025
2.10.0, 562
283, 651
354
642, 135, 074
444, 730, 193
623, 731, 3.10.1, 581, 315, 2.10.2
454, 633, 712, 245
084, 155, 741, 722
2.11.1750
483
065, 1.11.2, 751
3.11.0*For the calculated pattern, only reflections with intensities ≥ 1 are given**For the unit-cell parameters calculated from single-crystal data (Table 3)(bending vibrations of ­H 2 O molecules), 1167, 1028s(stretching vibrations of the tetrahedral framework), 774w,
728w, 700w, (mixed vibrations of the tetrahedral framework), 616, 551, 432 s (lattice modes involving predominantly bending vibrations of the tetrahedral framework andlibrational vibrations of ­H2O molecules).
There are distinct differences between the IR spectra ofmartinandresite and chemically-related zeolite harmotomein the wavenumber regions 1600–3700 cm−1 (vibrations of­H2O molecules) and 500–800 cm−1.

Chemical composition
Analytical data for martinandresite are given in Table 1.
Contents of other elements with atomic numbers > 8 are
below detection limits.
The empirical formula of martinandresite (based on
16 atoms Si + Al pfu) is N
­ a0.17K0.04Ba2.00(Al4.19Si11.81O32)
H 19.85O 9.93. T h e s i m p l i f i e d fo r m u l a i s­Ba2(Al4Si12O32)·10H2O, which requires BaO 21.72, ­Al2O3
14.44, ­SiO2 51.08, ­H2O 12.76, total 100.00 wt%.

13

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Table 3  Crystal data, datacollection information andstructure refinement details formartinandresite

Physics and Chemistry of Minerals (2018) 45:511–521
FormulaFormula weight
Temperature (K)Radiation and wavelength (Å)
Crystal system, space group, Z
Unit-cell dimensions (Å)

1414.90293(2)
MoKα; 0.71073
Orthorhombic, Pmmn, 1
a = 9.4640(5)b = 14.2288(6)c = 6.9940(4)941.82(8)V (Å3)
2.688
Absorption coefficient µ ­(mm−1)
689
F000
Crystal size (mm)0.07 × 0.09 × 0.10
Diffractometer
Xcalibur S CCD
Absorption correction
Multi-scan empirical absorption correction using sphericalharmonics, implemented in SCALE3 ABSPACK scaling
algorithm
θ range for data collection (°)
2.86–28.28
Index ranges–12 ≤ h ≤ 12, − 18 ≤ k ≤ 18, − 9 ≤ l ≤ 9
Reflections collected
17,030Independent reflections
1287 (Rint = 0.0925)
Independent reflections with I > 2σ(I)1278
Structure solution
Direct methods
Refinement method
Full-matrix least-squares on F2
Number of refined parameters
88
Final R indices [I > 2σ(I)]R1 = 0.0527, wR2 = 0.1156
R indices (all the data)
R1 = 0.0531, wR2 = 0.1158
GoF
1.418
1.21 (0.87 Å from Ba) and − 1.35 (1.51 Å from Ba)
Largest diff. peak and hole (e/Å3)
wR2 = Σw(|Fo|2 − |Fc|2)2/Σw|Fo|2)1/2; w = 1/[σ2(Fo2) + (0.0233P)2 + 6.3917P]
P = ([max of (0 or F02)] + 2Fc2)/3

The Gladstone–Dale compatibility index (Mandarino1981) calculated from the empirical formula and unitcell parameters found from single-crystal XRD data is
1 − (KP/KC) = 0.015 (superior).

X‑ray diffraction data and crystal structure
Powder X-ray diffraction data for martinandresite are listed
in the Table 2. Orthorhombic unit-cell parameters refinedfrom the powder data are: a = 9.465(2), b = 14.234(2),c = 7.000(2) Å, V = 943.0(6) Å3.
According to the single-crystal XRD data, martinandresite is orthorhombic, with the space group Pmmn and unitcell dimensions a = 9.4640(5), b = 14.2288(6), c = 6.9940(4)Å, and V = 941.82(8) Å3. A rather high value of Rint (9.25%)
is probably caused by relatively low quality of even thebest of tested crystals because of its slightly divergent character. The crystal structure was solved by direct methods
and refined using the SHELX-97 software package (Sheldrick 2008) to R = 0.0527 for 1278 unique reflections with
I > 2σ(I). The crystal data and the experimental details are

13

Na0.14Ba2.00[Si11.86Al4.14O32]·10H2O

presented in Table 3, atom coordinates, thermal displacement parameters, site occupancies and bond-valence sumsin Table 4, selected interatomic distances in Table 5.
The crystal structure of martinandresite is unique. It isbased on the Al–Si–O tetrahedral framework containing
four-, six- and eight-membered rings of tetrahedra (Fig. 5).
There are two crystallographically non-equivalent T sites
in the structure. Both are filled by Si and Al. No evidence
for Al and Si ordering was found. The mean T–O distances
for T(1) and T(2) sites are 1.630 and 1.634 Å, respectively.
Four-membered tetrahedral rings are linked to form double
crankshaft chains along the a axis. The chains are connected
via common vertices of tetrahedral rings to form six- andeight-membered tetrahedral rings (Fig. 5). The system ofchannels in the structure of martinandresite contains threesets. Two sets are parallel to the c and to a axes and their
openings are defined by eight-membered rings. Another setof channels is parallel to the b axis and its openings aredefined by six-membered rings of tetrahedra.
Extra-framework cations and ­H2O molecules are locatedin the channels. Ba cations are placed at the intersection of0.75
0.08452(15)0.58758(16)0.50.5656(5)0.0238(5)0.25000.25000.5424(6)0.4228(10)0.2500
0.75
0.75

Ba
T(1)
T(2)
O(1)
O(2)
O(3)
O(4)
O(5)
O(6)
O(7) = H2O
O(8) = H2O
O(9) = H2ONa

0.25
0.51364(10)0.64032(9)0.0− 0.0812(3)0.6059(3)0.1313(4)0.9604(5)0.75
0.75
0.8618(6)0.726(3)0.75

y/b0.80553(11)0.3028(2)0.0213(2)0.50.8248(7)0.1850(7)0.9011(10)0.3435(10)0.9812(9)0.5302(11)0.8454(11)0.489(3)0.869(2)z/c0.0213(2)0.0148(3)0.0147(3)0.0458(19)0.0339(11)0.0327(10)0.0292(14)0.0331(16)0.0294(14)0.051(2)0.051(2)0.127(18)0.08(4)**

Ueq
0.0208(4)0.0140(7)0.0142(7)0.051(5)0.044(3)0.033(2)0.020(3)0.015(3)0.031(4)0.062(6)0.036(4)0.19(3)U11
0.0162(3)0.0122(6)0.0067(6)0.051(4)0.022(2)0.029(2)0.026(3)0.035(3)0.016(3)0.057(5)0.070(6)0.12(5)

U22
0.0269(4)0.0182(7)0.0231(7)0.035(4)0.036(2)0.035(2)0.042(4)0.049(4)0.041(4)0.035(4)0.047(5)0.067(13)

U33
0.000
− 0.0005(5)− 0.0002(5)0.001(3)0.0151(19)0.0042(19)− 0.004(3)0.012(3)
0.000
0.000
0.015(4)− 0.005(16)

U23
0.000
0.0011(6)0.0031(6)− 0.018(4)0.002(2)− 0.009(2)
0.000
0.000
− 0.007(3)− 0.007(4)
0.000
0.000

U13

0.000
− 0.0011(5)0.0000(5)− 0.009(4)− 0.001(2)0.006(2)
0.000
0.000
0.000
0.000
0.000
0.000

U12

1
Si0.741Al0.259*
Si0.741Al0.259*
1
1
1
1
1
1
1
1
0.5*
0.072*

s.o.f.

2
8
8
4
8
8
4
4
4
4
4
4
2

Q

1.82
4.01
3.97
2.14
2.03
2.09
1.98
2.07
2.04
0.21
0.19

BVS

**Uiso*Fixed during the refinement

An insignificant K admixture (~ 3%, according to electron microprobe data) is assumed to be incorporated in Ba site. Na site was located from difference Fourier synthesis. We assume that some
additional Na cations were not localized due to their low occupancies. Na site was not taken into account for bond-valence analysis

x/a

Site

Table 4  Atom coordinates, thermal displacement parameters (Ueq, in Å2) and anisotropic thermal displacement parameters (Å2), site occupancy factors (s.o.f.), site multiplicities (Q) and bondvalence sums (BVS) [bond-valence parameters were taken from Brese and O’Keeffe (1991)] for martinandresite

Physics and Chemistry of Minerals (2018) 45:511–521
517

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Physics and Chemistry of Minerals (2018) 45:511–521

Table 5  Selected interatomic distances (Å) in the structure of martinandresite
Ba
O(7)
O(8)
O(3)
O(6)
O(5)
Na
O(6)
O(4)
O(9)
O(2)

2.861(8) × 2
2.914(8) × 2
2.965(5) × 4
3.144(6) × 2
3.170(7) × 2
2.116(7) × 2
2.332(9) × 2
2.68(3)2.986(5) × 4

T(1)
O(1)
O(2)
O(5)
O(3)

1.6061(15)1.627(4)1.634(2)1.653(4)

T(2)
O(2)
O(3)
O(4)
O(6)

1.625(4)1.632(5)1.635(3)1.642(2)the channels which are parallel to the c and to a axes andform twelve-fold polyhedra with Ba–O distances in the range
from 2.861(8) to 3.170(7) Å (Table 5). The environment ofFig. 5  Zeolite framework in the
structure of martinandresite inthree projections. T sites areshown as red circles

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Ba cations and coordination in the Ba-centered polyhedronare shown in Fig. 6. Na site with a very small occupancy
factor of 7% was found in the channels parallel to the a axis.
Na cations form four short bonds with O atoms of the framework with the distances from 2.116(7) to 2.332(9) Å and one
elongated bond 2.68(3) Å long with O(9) (oxygen atom ofwater molecule). Additionally, four bonds with Na–O distances of 2.986(5) Å could be included in the coordination
sphere of Na.
The values of bond-valence sums (Table 4) show that all
the oxygen atoms of the framework are saturated (the values
vary in the range from 1.98 to 2.14). Analysis of interatomic
distances allows to suppose the following rather weak hydrogen bonds involving three crystallographically non-equivalent water molecules [O(7), O(8) and O(9)]: O(7)⋯O(9),O(7)⋯O(8), O(8)⋯O(2), O(8)⋯O(8) and O(9)⋯O(4) withthe corresponding O–O distances of 3.13(11), 3.17(11),3.098(6), 3.18(18) and 3.05(3) Å, respectively.

Physics and Chemistry of Minerals (2018) 45:511–521

519

Fig. 6  Environment of Ba
cations (a) and coordination
polyhedron of Ba (b) in the
structure of martinandresite

Table 6  Comparative data for martinandresite and harmotome
MineralMartinandresite

Harmotome

FormulaCrystal system
Space group
a (Å)
b (Å)
c (Å)
β (°)
V (Å3)Z
Strong lines of the powder X-ray diffraction
pattern d, Å (I, %)Ba2(Al4Si12O32)·10H2O
Orthorhombic
Pmmn
9.464014.2288
6.994090941.82
1
7.86 (44)6.98 (74)6.26 (83)5.61 (100)3.933 (60)
3.191 (50)
3.170 (62)3.005 (79)2.816 (49)2.664 (45)3625, 3570sh, 3260sh, 1638, 1167,
1028s, 774w, 728w, 700w, 616, 551,
432s
Biaxial (−)α = 1.500
β = 1.512
γ = 1.515
2V = 55°
2.482 (meas.)2.495 (calc.)
This work

Ba2(Al4Si12O32)·12H2O
Monoclinic
P21/m
9.87–9.88
14.13–14.14
8.69–8.71
124.7–124.8
996.4–999.2
1
8.10 (40)
7.16 (50)
6.38 (100)4.08 (60)
3.24 (60)
3.17 (60)
3.13 (80)2.730 (60)2.698 (60)
2.670 (70)3587, 3540, 3474sh, 3280sh, 1652, 1140sh, 1024s,
794w, 719, 615, 425s

Wavenumbers of IR absorption bands (­ cm−1)
Optical data

Density (g cm−3)
Sources

Discussion
Martinandresite is chemically close to harmotome, ideally­Ba2[Al4Si12O32]·12H2O (Sadanaga et al. 1961; Rinaldi et al.
1974; Stuckenschmidt et al. 1990), which belongs to thephillipsite subgroup and is characterized by monoclinic symmetry, space group P21/m. The unit-cell dimensions a andBiaxial (+)α = 1.503–1.508
β = 1.505–1.509
γ = 1.508–1.514
2V = 80°
2.41–2.47 (meas.)2.448 (calc.)
Sahama and Lehtinen (1967), Rinaldi et al. (1974)
Perrotta (1976) and Stuckenschmidt et al. (1990)

b of martinandresite (9.46 and 14.23 Å, respectively) areclose to those of harmotome (9.87–9.88 and 14.13–14.14 Å),
while the c parameter is significantly different: 6.99 Å inorthorhombic martinandresite and 8.69–8.71 Å in monoclinic, with β = 124.8°, harmotome (Table 6). The frameworks of both martinandresite and harmotome (as well as theother zeolites of the phillipsite subgroup) contain four- and

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Physics and Chemistry of Minerals (2018) 45:511–521

Fig. 7  The crystal structures of martinandresite (a–c, left column) and harmotome (d–f, right column) drawn after Rinaldi et al. (1974)

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Physics and Chemistry of Minerals (2018) 45:511–521

eight-membered tetrahedral rings which form layers perpendicular to the a axis in martinandresite and approximately
perpendicular to the a axis in harmotome (Rinaldi et al.
1974). Structural and metrical similarity of martinandersite and merlinoite (which shows close relation to the phillipsite structure type) is also observed. Merlinoite, ideally­K5Ca2[Al9Si23O64]·22H2O and its varieties (Galli et al.
1979; Gatta et al. 2015 and references therein) are characterized by orthorhombic (pseudotetragonal) symmetry, spacegroup Immm with the unit-cell dimensions a = 14.116(7),b = 14.229(6), c = 9.946(6) Å (Galli et al. 1979) and thepresence of double crankshaft chains formed by four-membered tetrahedral rings with random (Si,Al) distribution
running along the c axis. Thus, the framework containing
four- and eight-membered tetrahedral rings with interconnecting eight-membered ring channels running parallel to
all the three axes is formed (Gatta et al. 2015). However,six-membered tetrahedral rings that occur in the structure ofmartinandresite are absent in the representatives of the phillipsite structure type as well as in merlinoite and its varieties.
The comparative data of martinandresite and harmotome are
given in Fig. 7 and Table 6.
Despite harmotome and martinandresite having similar composition, their crystal structures are different. This
fact has no unambiguous explanation. The structural differences may be a result of different conditions of crystallization (temperature, pressure and/or composition ofhydrothermal solution). Another cause of the structuraldifferences may be a different composition of extraframework cations: martinandresite is close to the barium
end-member, whereas most harmotome samples containsignificant amounts of Na + K + Ca.
Among natural zeolites, double crankshaft chains
formed by four-membered tetrahedral rings occur
also in the frameworks of gismondine, ideally­C a 2 [Al 4 Si 4 O 19 ]·9H 2 O (Fischer and Schramm 1971)
and in minerals of the gmelinite series [gmelinite-Ca,­( Ca 0.5 ,Sr,K,Na) 8 [Al 8 Si 16 O 48 ]·22H 2 O, gmelinite-Na(Na,K,Ca0.5)8[Al8Si16O48]·22H2O (Galli et al. 1982), andgmelinite-K, (K,Ca0.5,Na)8[Al8Si16O48]·22H2O (Vezzalini
et al. 1990)], where in the framework, there are 12-, 8-,
6- and 4-membered tetrahedral rings. It is worth to notethat natural Ba analogue of gismondine was reported byBraithwaite et al. (2001), and Ba-substituted gmelinite wasstudied by Vigdorchik and Malinovskii (1986). A significant amount of Ba was also reported for merlinoite (Gatta
et al. 2015 and references therein).

521
of structural investigations and Russian Science Foundation, grant no.
14-17-00048 (in part of investigations of chemical composition andphysical properties). The authors are grateful to Diego Gatta and an
anonymous reviewer for valuable comments.

References
Agilent Technologies (2014) CrysAlisPro Software system, version
1.171.37.34, Agilent Technologies UK Ltd, Oxford
Andres M (2009) Armenit, Erstfund mit Anfängerglück. Schweizer
Strahler 43(1):2–9 (German)
Braithwaite RSW, Dyer A, Lamb RPH, Wilson JI (2001) GismondineBa, a zeolite from the weathering of slags. J Russell Soc 7:83–85
Brese NE, O`Keeffe M (1991) Bond-valence parameters for solids.
Acta Crystallogr B 47:192–197
Fischer KF, Schramm V (1971) Crystal structure of gismondite, adetailed refinement. Adv Chem Ser 98:250–258
Galli E, Gottardi G, Pongiluppi D (1979) The crystal structure of thezeolite merlinoite. N Jb Min Mh 1–9
Galli E, Passaglia E, Zanazzi PF (1982) Gmelinite: structural refinement of sodium-rich and calcium-rich natural crystals. N Jb Min
Mh 145–155
Gatta GD, Rotiroti N, Bersani D, Bellatreccia F, Della Ventura G, Rizzato S (2015) A multi-methodological study of the (K, Ca)-varietyof the zeolite merlinoite. Mineral Mag 79:1755–1767
Graeser S, Hetherington CJ (2004) Ganterit—ein neues Mineral aus
den. Walliser Bergen Lapis 29(2):37–42 (German)
Graeser S, Hetherington CJ, Gieré R (2003) Ganterite, a new bariumdominant analogue of muscovite from the Berisal complex, Simplon region, Switzerland. Can Mineral 41:1271–1280
Hetherington CJ (2001) Barium anomalies in the Berisal complex,
Simplon region, Switzerland. PhD work, University of Basel,p 221
Mandarino JA (1981) The Gladstone–Dale relationship: Part IV. The
compatibility concept and its application. Can Miner 19:441–450
Perrotta AJ (1976) A low-temperature synthesis of a harmotome-typezeolite. Am Mineral 61:495–496
Rinaldi R, Pluth JJ, Smith JV (1974) Zeolites of the phillipsite family.
Refinement of the crystal structure of phillipsite and harmotome.
Acta Cryst B 30:2426–2433
Sadanaga R, Marumo F, Takéuchi Y (1961) The crystal structure ofharmotome, ­Ba2Si12Al4O32·12H2O. Acta Cryst 14:1153–1163
Sahama TG, Lehtinen M (1967) Harmotome from Korsnäs, Finland.
Mineral Mag 36:444–448
Sheldrick GM (2008) A short history of SHELX. Acta Cryst A
64:112–122
Stuckenschmidt E, Fuess H, Kvick A (1990) Investigation of the structure of harmotome by X-ray (293 K, 100 K) and neutron diffraction (15 K). Eur J Mineral 2:861–874
Vezzalini G, Quartieri S, Passaglia E (1990) Crystal structure of a
K-rich natural gmelinite and comparison with the other refined
gmelinite samples. N Jb Min Mh 504–516
Vigdorchik AG, Malinovskii YuA (1986) Crystal structure of Ba-substituted gmelinite B­ a4(Al8Si16O48)·nH2O. Sov Phys Crystallogr
31:519–521
Weiss S (2016) Armenit von der Wasenalp, Simplongebiet, Schweiz.
Lapis 41(7–8):40–48 (German)

Acknowledgements This work was financially supported by the Russian Foundation for Basic Research (Grant no. 18-55-18003) in part13