Hostname: page-component-7479d7b7d-c9gpj Total loading time: 0 Render date: 2024-07-12T15:26:09.001Z Has data issue: false hasContentIssue false

Aschamalmite (Pb6Bi2S9): crystal structure and ordering scheme for Pb and Bi atoms)

Published online by Cambridge University Press:  05 July 2018

A. M. Callegari*
Affiliation:
Dipartimento di Scienze della Terra, Università degli Studi di Pavia, via Ferrata 1, I-27100 Pavia, Italy
M. Boiocchi
Affiliation:
Centro Grandi Strumenti, Università degli Studi di Pavia, via Bassi 21, I-27100 Pavia, Italy

Abstract

The first single-crystal structure refinement of aschamalmite (Pb6Bi2S9) from Susa Valley (Piedmont, Italy) is reported. The mineral is monoclinic, C2/m, a = 13.719(1) Å, b = 4.132(1) Å, c = 31.419(3) Å, β = 90.94(1)º, V = 1 780.8(4) A ˚3, Z = 4. The Pb6Bi2S9 compound crystallizes also in an orthorhombic form as heyrovskyite (Cmcm) and our study is focused on understanding the reason leading to a change in symmetry. The aschamalmite structure forms because of ordering between Pb and Bi on the margins of the two octahedral layers that are symmetrically equivalent in heyrovskyite. The two alternate set of octahedral slabs are not related by a crystallographic mirror plane and the symmetry decreases to monoclinic. The cation ordering couples opposite sequences of Pb and Bi octahedra at the margins of slabs. In particular,the succession [Me4A]Bi-[Me5A]Pb-[Me4A]Bi-[Me5A]Pb faced to the series [Me4B]Pb- [Me5B]Bi-[Me4B]Pb-[Me5B]Bi occurs in about 70% of the unit-cells of the crystal,while the contrary sequence ([Me4A]Pb-[Me5A]Bi-[Me4A]Pb-[Me5A]Bi faced to [Me4B]Bi-[Me5B]Pb-[Me4B]Bi-[Me5B]Pb) occurs in the remaining unit-cells. The marginal octahedra have ideal populations (a.p.f.u.): [Me4A]1.40Bi+0.60Pb, [Me4B]1.40Pb+0.60Bi, [Me5A]1.40Pb+0.60Bi, [Me5B]1.40Bi+0.60Pb,in agreement with our structurerefinement results.

The probable site populations for pure heyrovskyite have been proposed,as well as the reasons that prevent the formation of a completely ordered monoclinic phase.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Altomare, A., Burla, M.C., Camalli, M., Cascarano, G.L., Giacovazzo, C., Guagliardi, A., Moliterni, A.G.G., Polidori, G. and Spagna, R. (1999). SIR97: a new tool for crystal structure determination and refinement. Journal of Applied Crystallography, 32, 115119.CrossRefGoogle Scholar
Armbruster, T. and Hummel, W. (1987) (Sb,Bi,Pb) ordering in sulfosalts: Crystal-structure refinement of a Bi-rich izoklakeite. American Mineralogist, 72, 821831.Google Scholar
Balestra, C. and Armellino, G. (2001) La miniera di Costabella. Notiziario di mineralogia del Ferrania Club, 15, 2026.Google Scholar
Balić-Žunić, T. and Vickovic, I. (1996) IVTON - Program for the calculation of geometrical aspects of crystal structures and some crystal chemical applications. Journal of Applied Crystallography, 29, 305306.CrossRefGoogle Scholar
Balić-Žunić, T. and Makovicky, E. (1996) Determination of the centroid or ‘the best centre’ of a coordination polyhedron. Acta Crystallographica B, 52, 7881.CrossRefGoogle Scholar
Berry, L.G. (1965) Recent advances in sulfide mineralogy. American Mineralogist, 50, 301313.Google Scholar
Borodaev, Y.S., Garavelli, A., Garbarino, C., Grillo, S.M., Mozgova, N.N., Paar, W.H., Topa, D. and Vurro, F. (2003) Rare sulfosalts from Vulcano, Aeolian Islands, Italy. V. selenian heyrovskyite. The Canadian Mineralogist, 41, 429440.CrossRefGoogle Scholar
Brese, N.E. and O’Keeffe, M. (1991) Bond-valence parameters for solids. Acta Crystallographica B, 47, 192197.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 B, 41, 244247. Bruker (2003). SAINT Software Reference Manual. Version 6. Bruker AXS Inc., Madison, Wisconsin, USA.Google Scholar
Busing, W.R., Martin, K.O. and Levy H.A. (1962) Orfls. Report Ornl-Tm-305.- Oak Ridge, Tn:Oak Ridge Natl. Lab. Tennessee, USA.Google Scholar
Callegari, A., Boiocchi, M. and Cech, G. (2008) Ritrovamento di aschamalmite in Val di Susa, Piemonte. Micro, 1, 125128.Google Scholar
Hummel, W. and Armbruster, T. (1987) Tl+, Pb2+, and Bi3+ bonding and ordering in sulfides and sulfosalts. Schweizerische Mineralogische und Petrographische Mitteilungen, 67, 213218.Google Scholar
Kupčik, V. (1984) Die Kristallstruktur des Minerals Eclarit (Cu,Fe)Pb9Bi12S28. Tschermaks Mineralogische und Petrographische Mitteilungen, 32, 259269.CrossRefGoogle Scholar
Liu, H. and Chang, L.L.Y. (1994) Lead and bismuth chalcogenide system. American Mineralogist, 79, 11591166.Google Scholar
Makovicky, E. (1977) Chemistry and crystallography of the lillianite homologous series. Part III. Related phases. Neues Jahrbuch fur Mineralogie Abhandlungen, 131, 187207.Google Scholar
Makovicky, E. and Karup-ϕller, S. (1977a) Chemistry and crystallography of the lillianite homologous series. Part. I: General properties and definitions. Neues Jahrbuch fur Mineralogie Abhandlungen, 130, 264287.Google Scholar
Makovicky, E. and Karup-ϕller, S. (1977b) Chemistry and crystallography of the lillianite homologous series. Part. II: Definition of new minerals: eskimoite, vikingite,ourayite and treasurite. Redefinition of schirmerite and new data on the lillianite-gustavite solid-solution series. Neues Jahrbuch fur Mineralogie Abhandlungen, 131, 5682.Google Scholar
Makovicky, E. and Balić-Žunić, T. (1993) Contribution to the crystal chemistry of thallium sulphosalts. II TlSb3S5 - the missing link of the lillianite homologous series. Neues Jahrbuch fur Mineralogie Abhandlungen, 165, 331344.Google Scholar
Makovicky, E. and Balić-Žunić, T. (1998) New measure of distortion for coordination polyhedra. Acta Crystallographica B, 54, 766773.CrossRefGoogle Scholar
Makovicky, E., Mumme, W.G. and Hoskins, B.F. (1991): The crystal structure of heyrovskite. The Canadian Mineralogist, 29, 553559. Makovicky, E., Balić-Žunić, T. and Topa, D. (2001) The crystal structure of neyite, Ag2Cu6Pb25Bi26S68. The Canadian Mineralogist, 39, 13651376.Google Scholar
Moëlo, Y., Makovicky, E., Mozgova, N.N., Jambor, J.L., Cook, N., Pring, A., Paar, W.H., Nickel, E.H., Graeser, S., Karup-ϕller, S., Balic-Žumc, T., Mumme, W.G., Vurro, F., Topa, D., Bindi, L., Bente, K. and Shimizu, M. (2008) Sulfosalt systematics: a review. Report of the sulfosalt subcommittee of the IMA Commission on Ore Mineralogy. European Journal of Mineralogy, 20, 746.CrossRefGoogle Scholar
Mumme, W.G., Niedermayr, G., Kelly, P.R. and Paar, W.H. (1983) Aschamalmite Pb5.92Bi2.06S9, from Untersulzbach Valley in Salzburg, Austria. Neues Jahrbuch fUr Mineralogie Monatshefte, 433444. Perchiazzi, N. (1989) Aschamalmite: secondo ritrova- mento in natura presso l’Alpe Cedo, Val d’Ossola. Rivista Mineralogica Italiana, 4, 238240.Google Scholar
Shannon, R.D. (1976) Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides. Acta Crystallographica A, 32, 751767.CrossRefGoogle Scholar
Sheldrick, G.M. (1996) SADABS Siemens Area Detector Absorption Correction Program. University of Gottingen, Germany.Google Scholar
Takeuchi, Y. and Takagi, J. (1974) The Structure of Heyrovskyite (6PbS-Bi2S3). Proceedings of the Japan Academy, 50, 7679.Google Scholar
Wyckoff, R.W.G. (1963) Pp. 85237 in: Crystal Structures, I. 2nd edition (rocksalt structure). Interscience Publishers, New York.Google Scholar
Supplementary material: File

Callegari and Boiocchi supplementary material

Cif file

Download Callegari and Boiocchi supplementary material(File)
File 30.2 KB