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Raberite, Tl5Ag4As6SbS15, a new Tl-bearing sulfosalt from Lengenbach quarry, Binn valley, Switzerland: description and crystal structure

Published online by Cambridge University Press:  05 July 2018

L. Bindi ,
F. Nestola ,
A. Guastoni ,
L. Peruzzo ,
M. Ecker  and
R. Carampin
L. Bindi*
Affiliation:
Dipartimento di Scienze della Terra, Universitá degli Studi di Firenze, Via G. La Pira 4, I-50121 Firenze, Italy CNR - Istituto di Geoscienze e Georisorse, Sezione di Firenze, Via G. La Pira 4, I-50121 Firenze, Italy
F. Nestola
Affiliation:
Dipartimento di Geoscienze, Universitá degli Studi di Padova, Via Gradenigo 6, I-35131 Padova, Italy
A. Guastoni
Affiliation:
Museo di Mineralogia, Universitá degli Studi di Padova, Palazzo Cavalli, Via Matteotti 30, I-35121, Padova, Italy
L. Peruzzo
Affiliation:
CNR - Istituto di Geoscienze e Georisorse, Sezione di Padova, Via Gradenigo 6, I-35131, Padova, Italy
M. Ecker
Affiliation:
Pfarrbrunnenstrasse 18, D-66578 Schiffweiler, Germany
R. Carampin
Affiliation:
CNR - Istituto di Geoscienze e Georisorse, Sezione di Padova, Via Gradenigo 6, I-35131, Padova, Italy
*
*E-mail: [email protected]
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Abstract

Raberite, ideally Tl5Ag4As6SbS15, is a new mineral from Lengenbach quarry in the Binn Valley, Valais, Switzerland. It occurs very rarely as euhedral crystals up to 150 m m across associated with yellow needle-like smithite, realgar, hatchite and probable trechmannite, edenharterite, jentschite and two unidentified sulfosalts. Raberite is opaque with a metallic lustre and has a dark brown–red streak. It is brittle with a Vickers hardness (VHN10) of 52 kg mm–2 (range 50–55) corresponding to a Mohs hardness of 2½–3. In reflected light raberite is moderately bireflectant and very weakly pleochroic from light grey to a slightly greenish grey. It is very weakly anisotropic with greyish to light blue rotation tints between crossed polars. Internal reflections are absent. Reflectance percentages for the four COM wavelengths [listed as Rmin, Rmax, (λ)] are 30.6, 31.8 (471.1 nm), 28.1, 29.3 (548.3 nm), 27.1, 28.0 (586.6 nm), and 25.8, 26.9 (652.3 nm).

Raberite is triclinic, space group P1, with a = 8.920(1), b = 9.429(1), c = 20.062(3) Å, α = 79.66(1), β = 88.84(1), γ = 62.72(1)º, V = 1471.6(4) Å3 and Z = 2. The crystal structure [R1 = 0.0827 for 2110 reflections with I > 2σ(I)] consists of columns of nine-coordinate Tl atoms forming irregular polyhedra extending along [001] and forming sheets parallel to (010). The columns are decorated by cornersharing MS3 pyramids (M = As, Sb) and linked by AgS3 triangles. Of the seven M positions, one is dominated by Sb and the others by As; the mean M-S bond distances reflect As ↔ Sb substitution at these sites.

The eight strongest lines in the powder diffraction pattern [dcalc in Å (I) (hkl)] are: 3.580 (100) (13); 3.506 (58) (23); 3.281 (73) (006); 3.017 (54) (3); 3.001 (98) (133); 2.657 (51) (226); 2.636 (46) (300); 2.591 (57) (330). A mean of 9 electron microprobe analyses gave Tl 39.55(13), Ag 18.42(8), Cu 0.06(2), As 17.08(7), Sb 5.61(6), S 19.15(11); total 99.87 wt.%, which corresponds to Tl4.85Ag4.28Cu0.02As5.72Sb1.16S14.97 with 31 atoms per formula unit. The new mineral has been approved by the IMA-CNMNC Commission (IMA 2012-017) and is named for Thomas Raber, an expert on Lengenbach minerals.

Keywords

raberitenew mineralTl-sulfosaltscrystal structureLengenbachSwitzerland
Type
Research Article
Information
Mineralogical Magazine , Volume 76 , Issue 5 , October 2012 , pp. 1153 - 1163
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2016

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References

Balić-Ž unić, T., Makovicky, E., Karanović, L., Poleti, D. and Graeser, S. (2006) The crystal structure of gabrielite, Tl2AgCu2As3S7, a new species of thallium sulfosalt from Lengenbach, Switzerland. The Canadian Mineralogist, 44, 141–158.CrossRefGoogle Scholar
Bindi, L., Evain, M. and Menchetti, S. (2006) Temperature dependence of the silver distribution in the crystal structure of natural pearceite, (Ag,Cu)16(As,Sb)2S11. Acta Crystallographica, B62, 212–219.CrossRefGoogle Scholar
Bindi, L., Evain, M. and Menchetti, S. (2007) Complex twinning, polytypism and disorder phenomena in the crystal structures of antimonpearceite and arsenpolybasite. The Canadian Mineralogist, 45, 321–333.CrossRefGoogle Scholar
Brese, N.E. and O’Keeffe, M. (1991) Bond-valence parameters for solids. Acta Crystallographica, B47, 192–197.CrossRefGoogle Scholar
Burry, G., Graeser, S., Marumo, F. and Nowacki, W. (1965) Imhofit, ein neues Thallium- Arsensulfosalz aus dem Lengenbach (Binnatal, Kanton Wallis). Chimia, 19, 499–500.Google Scholar
Evain, M., Bindi, L. and Menchetti, S. (2006) Structural complexity in minerals: twinning, polytypism and disorder in the crystal structure of polybasite, (Ag,Cu)16(Sb,As)2S11. Acta Crystallographica, B62, 447–456.CrossRefGoogle Scholar
Graeser, S. and Edenharter, A. (1997) Jentschite (TlPbAs2SbS6) - a new sulfosalt mineral from Lengenbach, Binntal (Switzerland). Mineralogical Magazine, 61, 131–137.CrossRefGoogle Scholar
Graeser, S. and Schwander, H. (1992) Edenharterite (TlPbAs3S6): a new mineral from Lengenbach, Binntal (Switzerland). European Journal of Mineralogy, 4, 1265–1270.CrossRefGoogle Scholar
Graeser, S., Schwander, H., Wulf, R. and Edenharter, A. (1992) Erniggliite (Tl2SnAs2S6), a new mineral from Lengenbach, Binntal (Switzerland): description and crystal structure determination based on data from synchrotron radiation. Schweizerische mineralogische und petrographische Mitteilungen, 72, 293–305.Google Scholar
Graeser, S., Schwander, H., Wulf, R. and Edenharter, A. (1995) Stalderite TlCu(Zn,Fe,Hg)2As2S6 - a new mineral related to routhierite: description and crystal structure determination. Schweizerische mineralogische und petrographische Mitteilungen, 75, 337–345.Google Scholar
Graeser, S., Berlepsch, P., Makovicky, E. and Balić- Ž unić, T. (2001) Sicherite, TlAg2(As,Sb)3S6, a new sulfosalt mineral from Lengenbach (Binntal, Switzerland): description and structure determina- tion. American Mineralogist, 86, 1087–1093.CrossRefGoogle Scholar
Graeser, S., Topa, D., Balić-Zunić, T. and Makovicky, E. (2006) Gabrielite, Tl2AgCu2As3S7, a new species of thallium sulfosalt from Lengenbach, Binntal, Switzerland. The Canadian Mineralogist, 44, 135–140.CrossRefGoogle Scholar
Graeser, S., Cannon, R., Drechsler, E., Raber, T. and Roth, P. (2008) Faszination Lengenbach Abbau- Forschung-Mineralien 1958–2008. Kristallographik Verlag, Achberg, Germany.Google Scholar
Huang, D.P. and Corbett, J.D. (1998) A5TaAs4Tl2 (A = Rb, K). Transition-metal Zintl phases with a novel complex ion: synthesis, structure, and bonding. Inorganic Chemistry, 37, 4006–4010.CrossRefGoogle Scholar
Ibers, J.A. and Hamilton, W.C. (editors) (1974) International Tables for X-ray Crystallography, volume. IV. Kynock Press, Birmingham, UK.Google Scholar
Nestola, F., Guastoni, A., Bindi, L. and Secco L. (2010) Dalnegroite, Tl5-xPb2x(As,Sb)21-xS34, a new thallium sulphosalt from Lengenbach quarry, Binntal, Canton Valais, Switzerland. Mineralogical Magazine, 73, 1027–1032.CrossRefGoogle Scholar
Shannon, R.D. (1976) Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides. Acta Crystallographica, A32, 751–767.CrossRefGoogle Scholar
Sheldrick, G.M. (2008) A short history of SHELX. Acta Crystallographica, A64, 112–122.CrossRefGoogle Scholar
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