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Švenekite, Ca[AsO2(OH)2]2, a new mineral from Jáchymov, Czech Republic

Published online by Cambridge University Press:  05 July 2018

P. Ondruš ,
R. Skála ,
J. Plášil ,
J. Sejkora ,
F. Veselovský ,
J. Čejka ,
A. Kallistová ,
J. Hloušek ,
K. Fejfarová  and
R. Škoda
...Show all authors
P. Ondruš
Affiliation:
Biskupský dvůr 2, Prague 1, 110 00, Czech Republic
R. Skála
Affiliation:
Institute of Geology ASCR, v.v.i., Rozvojová 269, Prague 6, 165 00, Czech Republic
J. Plášil*
Affiliation:
Institute of Physics ASCR, v.v.i., Na Slovance 2, Prague 8, 182 21, Czech Republic
J. Sejkora
Affiliation:
Department of Mineralogy and Petrology, National Museum, Cirkusová 170, 193 00, Prague 9, Czech Republic
F. Veselovský
Affiliation:
Czech Geological Survey, Klárov 3, 118 21, Prague 1, Czech Republic
J. Čejka
Affiliation:
Department of Mineralogy and Petrology, National Museum, Cirkusová 170, 193 00, Prague 9, Czech Republic
A. Kallistová
Affiliation:
Institute of Geology ASCR, v.v.i., Rozvojová 269, Prague 6, 165 00, Czech Republic
J. Hloušek
Affiliation:
U Roháčových kasáren 24, 100 00, Prague 10, Czech Republic
K. Fejfarová
Affiliation:
Institute of Physics ASCR, v.v.i., Na Slovance 2, Prague 8, 182 21, Czech Republic
R. Škoda
Affiliation:
Department of Geological Sciences, Masaryk University, Kotlářská 2, Brno, 611 37, Czech Republic
M. Dušek
Affiliation:
Institute of Physics ASCR, v.v.i., Na Slovance 2, Prague 8, 182 21, Czech Republic
A. Gabašová
Affiliation:
Czech Geological Survey, Klárov 3, 118 21, Prague 1, Czech Republic
V. Machovič
Affiliation:
Institute of Chemical Technology, Prague, Technická 5, 16628, Prague 6, Czech Republic Institute of Rock Structures and Mechanics ASCR, v.v.i., V Holešovičkách 41, 18209, Prague 8, Czech Republic
L. Lapčák
Affiliation:
Institute of Chemical Technology, Prague, Technická 5, 16628, Prague 6, Czech Republic
*
* E-mail: [email protected]
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Abstract

Švenekite (IMA 99-007), Ca[AsO2(OH)2]2, is a rare supergene arsenate mineral occurring in the Geschieber vein, Jáchymov ore district, Western Bohemia, Czech Republic. It grows directly on the granite rocks and occurs isolated from other arsenate minerals otherwise common in Jáchymov. Švenekite usually forms clear transparent coatings composed of indistinct radiating to rosette-shaped aggregates up to 3 mm across. They are composed of thin lens- or bladed-shaped crystals, usually 100 – 150 μm long. Švenekite is transparent to translucent and has a white streak and a vitreous lustre; it does not fluoresce under ultraviolet light. Cleavage is very good on {010}. The Mohs hardness is ∼2. Švenekite is biaxial, non-pleochroic. The refractive indices are α' = 1.602(2), γ' = 1.658(2). The empirical formula of švenekite (based on As + P + S = 2 a.p.f.u., an average of 10 spot analyses) is (Ca1.00Mg0.01)Σ1.01[AsO2(OH)2]1.96[PO2(OH)2]0.03(SO4)0.01. The simplified formula is Ca[AsO2(OH)2]2 and requires CaO 17.42, As2O571.39, H2O 11.19, total 100.00 wt.%. Raman and infrared spectroscopy exhibit dominance of O – H vibrations and vibration modes of distorted tetrahedral AsO2(OH)2 units. Švenekite is triclinic, space group P, with a = 8.5606(5), b = 7.6926(6), c = 5.7206(4) Å, α = 92.605(6), β = 109.9002(6), γ = 109.9017(6)º, and V = 327.48(4) Å3, Z = 2, Dcalc = 3.26 g·cm–3. The a:b:c ratio is 0.7436:1:1.1082 (for single-crystal data). The six strongest diffraction peaks in the X-ray powder diffraction pattern are [d (Å)/I(%)/(hkl)]: 3.968(33)(20); 3.766(35)(2); 3.697(49)(101); 3.554(100)(020); 3.259(33)(20); 3.097(49)(11). The crystal structure of švenekite was refined from single-crystal X-ray diffraction data to R1 = 0.0250 based on 1309 unique observed, and to wR2 = 0.0588, for all 1588 unique reflections (with GOFall = 1.20). The structure of švenekite consists of sheets of corner-sharing CaO8 polyhedra and AsO2 OH2 groups, stacked parallel to (001). Adjacent sheets are linked by hydrogen bonds. The švenekite structure possesses very short symmetrical hydrogen bonds (with the D–H lengths ∼1.22 Å). The mineral is named to honour Jaroslav Švenek, the former curator of the mineralogical collection of the National Museum in Prague, Czech Republic.

Keywords

švenekitenew mineralcalcium bis (dihydrogen-arsenate)crystal structureJáchymov
Type
Research Article
Information
Mineralogical Magazine , Volume 77 , Issue 6 , August 2013 , pp. 2711 - 2724
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2013

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Footnotes

†

Deceased June 22, 2006

References

Boudjada, A. and Guital, J.C. (1981) Structure cristalline d’un orthoarséniate acide de fer(III) pentahydrate ´: Fe(H2AsO4)3·5H2O. Acta Crystallographica, B37, 1402–1405 CrossRefGoogle Scholar
Brown, I.D. (2002) The Chemical Bond in Inorganic Chemistry. The Bond Valence Model. Oxford University Press, Oxford, UK.Google Scholar
Brown, I.D. and Shannon, R.D. (1973) Empirical bondstrength bond-length curves for oxides. Acta Crystallographica, A29, 266–282 CrossRefGoogle Scholar
Brown, I.D. and Altermatt, D. (1985) Bond-valence parameters obtained from a systematic analysis of the inorganic crystal structure database. Acta Crystallographica, B41, 244–248 CrossRefGoogle Scholar
Brugger, J., Krivovichev, S.V., Kolitsch, U., Meisser, N., Andrut, M., Ansermet, S. and Burns, P.C. (2002) Description and crystal structure of manganlotharmeyerite, Ca[Mn3+,□,Mg]2{AsO4,[AsO2(OH)2]}2 (OH,H2O)2 from the Starlera Mn deposit, Swiss Alps, and a redefinition of lotharmeyerite. The Canadian Mineralogist, 40, 1597–1608 CrossRefGoogle Scholar
Bruker-AXS, (2008) TOPAS v. 4: General profile and structure analysis software for powder diffraction data. User’s Manual, Bruker AXS, Karlsruhe, Germany.Google Scholar
Burnham, C.W. (1962) Lattice constant refinement. Carnegie Institute Washington Year Book, 61, 132–135 Google Scholar
Chiari, G. and Ferraris, G. (1971) The crystal structure of calcium dihydrogen arsenate, Ca(H2AsO4)2 . Atti della Accademia delle Scienze di Torino, Classe di Scienze Fisiche, Matematiche e Naturali, 105, 725–743 Google Scholar
Cooper, M.A. and Hawthorne, F.C. (2000) Highly undersaturated anions in the crystal structure of andyrobertsite – calcioandyrobertsite, a doubly acid arsenate of the form K(Cd,Ca)[Cu5(AsO4)4 {As(OH)2O2}](H2O)2 . The Canadian Mineralogist, 38, 817–830 CrossRefGoogle Scholar
Cooper, M.A., Hawthorne, F.C., Pinch, W.W. and Grice, J.D. (1999) Andyrobertsite and calcio-andyrobertsite: two new minerals from the Tsumeb mine, Tsumeb, Namibia. The Mineralogical Record, 30, 181–186 Google Scholar
Ferraris, G., Jones, D.W. and Yerkess, J. (1972) A neutron diffraction study of the crystal structure of calcium bis(dihydrogen arsenate), Ca(H2AsO4)2 . Acta Crystallographica, B28, 2430–2437 CrossRefGoogle Scholar
Hoppe, R. (1979) Effective coordination numbers (ECoN) and mean fictive ionic radii (MEFIR). Zeitschrift für Kristallographie, 150, 23–52 CrossRefGoogle Scholar
Keller, P. (1971) Die Kristallchemie der Phosphat- und Arsenatminerale unter besonderer Berücksichtung der Kationen-Koordinationspolyeder und des Kristallwassers, Teil A. Die Anionen der Phosphatund Arsenatminerale. Neues Jahrbuch fü r Mineralogie, Monatshefte 1971, 491–510 Google Scholar
Kraus, W. and Nolze, G. (2000) PowderCell 2.4. Federal Institute for Materials Research and Testing, Berlin.Google Scholar
Libowitzky, E. (1999) Correlation of O-H stretching frequencies and O-H_O hydrogen bond lengths in minerals. Monatshefte für Chemie, 130, 1047–1059 CrossRefGoogle Scholar
Momma, K. and Izumi, F. (2008) VESTA: a threedimensional visualization system for electronic and structural analysis. Journal of Applied Crystallography, 41, 653–658 CrossRefGoogle Scholar
Myneni, S.C.B., Traina, S.J., Waychunas, G.A. and Logan, T.J. (1998) Experimental and theoretical vibrational spectroscopic evaluation of arsenate coordination in aqueous solutions, solids, and at mineral–water interfaces. Geochimica et Cosmochimica Acta, 62, 3285–3300 CrossRefGoogle Scholar
Ondruš, P., Veselovský, F., Skála, R., Císařová, I., Hloušek, J., Frýda, J., Vavřín, I., Čejka, J. and Gabašová, A. (1997) New naturally occurring phases of secondary origin from Jáchymov (Joachimsthal). Journal of the Czech Geological Society, 42, 77–107 Google Scholar
Ondruš, P., Veselovský, F., Gabašová, A., Hloušek, J. and Šrein, V. (2003a) Supplement to secondary and rock-forming minerals of the Jáchymov ore district. Journal of the Czech Geological Society, 48(3–4) , 149–155 Google Scholar
Ondruš, P., Veselovský, F., Gabašová, A., Hloušek, J., Šrein, V., Vavřín, I., Skála, R., Sejkora, J. and Drábek, M. (2003b) Primary minerals of the Jáchymov ore district. Journal of the Czech Geological Society, 48(3–4) , 19–147 Google Scholar
Petříček, V., Dušek, M. and Palatinus, L. (2006) Jana2006. The crystallographic computing system. Institute of Physics, Prague, Czech Republic.Google Scholar
Pouchou, J.L. and Pichoir, F. (1985) “PAP” (jrZ) procedure for improved quantitative microanalysis. Pp. 104–106 in: Microbeam Analysis (J.T. Armstrong, editor). San Francisco Press, San Francisco, California, USA.Google Scholar
Raade, G., Mladeck, M.H., Kristiansen, R. and Din, V.K. (1984) Kaatialaite, a new ferric arsenate from Finland. American Mineralogist, 69, 383–387 Google Scholar
Robinson, K., Gibbs, G.V. and Ribbe, P.H. (1971) Quadratic elongation: A quantitative measure of distortion in coordination polyhedra. Science, 172, 567–570 CrossRefGoogle ScholarPubMed
Sarp, H. and Černý, R. (2004) Calcio-andyrobertsite-2O, KCaCu5(AsO4)4[AsO2(OH)2]·2H2O: its description, crystal structure and relation with calcio-andyrobertsite- 1M. European Journal of Mineralogy, 16, 163–169 CrossRefGoogle Scholar
Sejkora, J. and Kouřimský, J. (2005): Atlas minerálů CČeské a Slovenské republiky. 376 pp., Academia, Prague.Google Scholar
Tvrdý, J. and Plášil, J. (2010) Jáchymov - Reiche Erzlagersta¨ tte und Radonbad im bö hmischen Westerzgebirge. Aufschluss, 61, 277–292 Google Scholar
Vansant, F.K., Van Der Veken, B.J. and Desseyn, H.O. (1973) Vibrational analysis of arsenic acid and its anions. I. Description of the Raman spectra. Journal of Molecular Structure, 15, 425–437 CrossRefGoogle Scholar