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Coquandite, Sb6+xO8+x(SO4)(OH)x·(H2O)1–x (x = 0.3), from the Cetine mine, Tuscany, Italy: crystal structure and revision of the chemical formula

Published online by Cambridge University Press:  05 July 2018

L. Bindi ,
C. Biagioni ,
L. Ceccantini ,
M. Batoni  and
S. Menchetti
L. Bindi*
Affiliation:
Dipartimento di Scienze della Terra, Università degli Studi di Firenze, Via G. La Pira 4, I-50121 Florence, Italy CNR – Istituto di Geoscienze e Georisorse, Sezione di Firenze, Via G. La Pira 4, I-50121 Florence, Italy
C. Biagioni
Affiliation:
Dipartimento di Scienze della Terra, Università di Pisa, Via S. Maria 53, I-56126 Pisa, Italy
L. Ceccantini
Affiliation:
Gruppo Mineralogico Fiorentino, Via Poggio Bracciolini 23, I-56126 Florence, Italy
M. Batoni
Affiliation:
Gruppo Mineralogico Fiorentino, Via Poggio Bracciolini 23, I-56126 Florence, Italy
S. Menchetti
Affiliation:
Dipartimento di Scienze della Terra, Università degli Studi di Firenze, Via G. La Pira 4, I-50121 Florence, Italy
*
* E-mail: luca.bindi@unifi.it
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Abstract

The crystal structure of the mineral coquandite, a rare Sb oxy-sulfate hydrate, was solved using intensity data collected from a crystal from the Cetine mine, Tuscany, Italy. This study revealed that the structure is triclinic, space group P, with a = 11.4292(5), b = 29.772(1), c = 11.2989(5) Å, α = 91.152(3), β = 119.266(4), γ = 92.624(3)° and V = 3346.4(2) Å3. The refinement of an anisotropic model led to an R index of 0.0347 for 21,061 independent reflections. Thirty-two Sb sites, five S sites and 67 oxygen sites occur in the crystal structure of coquandite. Sb atoms display the characteristic SbO3E and SbO4E coordinations whereas S fills (SO4) tetrahedral groups. These atoms are arranged in five symmetry-independent layers perpendicular to b*. Four of them and their centrosymmetrical counterparts form complex modules stacked along b* and bonded through two Sb atoms and H bonds. The complex H bonding system in the structure is discussed. On the basis of information gained from this characterization, the crystal-chemical formula was revised according to the structural results, yielding Sb6+xO8+x(SO4)(OH)x·(H2O)1–x (Z = 10) with x = 0.3 instead of Sb6O8(SO4)·H2O (Z = 12) as reported previously. A recalculation of the chemical data listed in the scientific literature for coquandite according to the structural results obtained here leads to a satisfactory agreement.

Keywords

coquanditeSb-sulfatesstructure solutioncrystal-structure refinementCetine mine
Type
Research Article
Information
Mineralogical Magazine , Volume 78 , Issue 4 , August 2014 , pp. 871 - 888
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2014

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References

Bovin, J.O. (1976) The crystal structure of the antimony(III) oxide sulphate Sb6O7(SO4)2. Acta Crystallographica, B32, 1771–1777.CrossRefGoogle Scholar
Brese, N.E. and O’Keeffe, M. (1991) Bond-valence parameters for solids. Acta Crystallographica, B47, 192–197.CrossRefGoogle Scholar
Cipriani, N., Menchetti, S., Orlandi, P. and Sabelli, C. (1980a) Peretaite, CaSb4O4(OH)2(SO4)2·2H2O, a new mineral from Pereta, Tuscany, Italy. American Mineralogist, 65, 936–939.Google Scholar
Cipriani, N., Menchetti, S. and Sabelli, C. (1980b) Klebelsbergite and another antimony mineral from Pereta, Tuscany, Italy. Neues Jahrbuch für Mineralogie, Monatshefte, 1980, 223–229.Google Scholar
Downs, R.T., Bartelmehs, K.L., Gibbs, G.V. and Boisen, M.B. Jr. (1993) Interactive software for calculating and displaying X-ray or neutron powder diffractometer patterns of crystalline materials. American Mineralogist, 78, 1104–1107.Google Scholar
Fei, H., Han, C.S. and Oliver, S.R.J. (2012) A cationic antimonite chain templated by sulfate: [Sb6O7 4+][(SO4 2–)2]. Inorganic Chemistry, 51, 8655–8657.CrossRefGoogle Scholar
Ferraris, G. and Ivaldi, G. (1988) Bond valence vs bond length in O_O hydrogen bonds. Acta Crystallographica, B44, 341–344.CrossRefGoogle Scholar
Galy, J., Meunier, G., Andersson, S. and Åström, A. (1975) Stéréochimie des eléments comportant des paires non liées: Ge (II), As (III), Se (IV), Br (V), Sn (II), Sb (III), Te (IV), I (V), Xe (VI), Tl (I), Pb (II), et Bi (III) (oxydes, fluorures et oxyfluorures). Journal of Solid State Chemistry, 13, 142–159.CrossRefGoogle Scholar
Herrendorf, W. (1993) Habitus. Unpublished PhD thesis, University of Karlsruhe, Germany.Google Scholar
Ibers, J.A. and Hamilton, W.C. (editors) (1974) International Tables for X-ray Crystallography, vol. IV. Kynock, Dordrecht, The Netherlands, 366 pp.Google Scholar
Krivovichev, S.V. (2009) Structural Crystallography of Inorganic Oxysalts. International Union of Crystallography, Oxford University Press, Oxford, UK, 308 pp.CrossRefGoogle Scholar
Menchetti, S. and Sabelli, C. (1980a) Peretaite, CaSb4O4(OH)2(SO4)2·2H2O: Its atomic arrangement and twinning. American Mineralogist, 65, 940–946.Google Scholar
Menchetti, S. and Sabelli, C. (1980b) The crystal structure of klebelsbergite Sb4O4(OH)2SO4 . American Mineralogist, 65, 931–935.Google Scholar
Mercier, P.R., Douglade, J. and Theobald, F. (1975) Structure cristalline de Sb2O3.2SO3. Acta Crystallographica, B31, 2081–2085.CrossRefGoogle Scholar
Mills, S.J., Christy, A.G., Chen, E.C.-C. and Raudsepp, M. (2009) Revised values of the bond valence parameters for [6]Sb(V)–O and [3–11]Sb(III)–O. Zeitschrift für Kristallographie, 224, 423–431.CrossRefGoogle Scholar
Oxford Diffraction (2006) CrysAlis RED (Version 1.171. 31. 2) and ABSPACK in CrysAlis RED. Oxford Diffraction Ltd., Abingdon, Oxfordshire, UK.Google Scholar
Sabelli, C., Orlandi, P. and Vezzalini, G. (1992) Coquandite, Sb6O8(SO4)·H2O, a new mineral from Pereta, Tuscany, Italy, and two other localities. Mineralogical Magazine, 56, 599–603.CrossRefGoogle Scholar
Sheldrick, G.M. (2008) A short history of SHELX. Acta Crystallographica, A64, 112–122.CrossRefGoogle Scholar
Stoe, and Cie, (1996) X-shape (version 1.02). Stoe & Cie, Darmstadt, Germany.Google Scholar
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Table 5. Structure factors

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