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GEOREF RECORD

Crystal structure of natural orthorhombic Ag (sub 0.71) Pb (sub 1.52) Bi (sub 1.32) Sb (sub 1.45) S (sub 6) , a lillianite homologue with N=4; comparison with gustavite

Richard Pazout and Michal Dusek
Crystal structure of natural orthorhombic Ag (sub 0.71) Pb (sub 1.52) Bi (sub 1.32) Sb (sub 1.45) S (sub 6) , a lillianite homologue with N=4; comparison with gustavite
European Journal of Mineralogy (October 2010) 22 (5): 741-750

Abstract

The crystal structure of natural orthorhombic Ag (sub 0.71) Pb (sub 1.52) Bi (sub 1.32) Sb (sub 1.45) S (sub 6) , a lillianite homologue with N=4, from hydrothermal veins at Kutna Hora in central Bohemia, Czech Republic, has been refined from single-crystal X-ray data to final R (sub w) =5.08%. The symmetry is orthorhombic, space group Cmcm, with a=4.2539(8), b=13.3094(8), c=19.625(1) Aa, V=1111.1(2) Aa (super 3) , Z=4. On the basis of electron-microprobe analysis, the formula is Ag (sub 0.69) Pb (sub 1.56) (Bi (sub 1.32) Sb (sub 1.37) ) (sub Sigma =2.69) (S (sub 6.04) Se (sub 0.01) ) (sub Sigma 6.05) with N (sub chem) =3.94, Bi/(Bi+Sb)=0.49 and a gustavite substitution percentage L%=70.5, which characterize the phase as a natural orthorhombic Sb-Bi (super 4,4) L member of the lillianite homologous series. The structure contains seven independent positions: three metal sites M1, M2 and M3 and four sulphur positions. The crystal structure consists of blocks of diagonal chains of four octahedra M1 (Bi/Ag/Sb)-M2 (Sb/Pb/Bi)-M2-M1 separated by Pb atoms in bicapped trigonal prismatic coordination of the site M3. The marginal octahedron of the chain of four octahedra is formed by one mixed site M1 containing 52% Bi, 35.6% Ag and 12.4% Sb while the central M2 octahedron is a mixed site containing 60.1% Sb, 25.9% Pb and 14% Bi. The mixed population of the M1 site results in orthorhombic symmetry, space group Cmcm, with a 4 Aaa-repeat while in natural gustavite, the alternating occupation of the M1 site by Ag and Bi atoms (which are thus two sites M1a and M1b) reduces the symmetry to monoclinic, space group P2 (sub 1) /c, with an 8 Aarepeat. The structure is similar to that of Ag-free lillianite.


ISSN: 0935-1221
EISSN: 1617-4011
Serial Title: European Journal of Mineralogy
Serial Volume: 22
Serial Issue: 5
Title: Crystal structure of natural orthorhombic Ag (sub 0.71) Pb (sub 1.52) Bi (sub 1.32) Sb (sub 1.45) S (sub 6) , a lillianite homologue with N=4; comparison with gustavite
Affiliation: Institute of Chemical Technology, Prague, Czech Republic
Pages: 741-750
Published: 201010
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 32
Accession Number: 2010-098047
Categories: Mineralogy of non-silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 8 tables
N49°58'00" - N49°58'00", E15°18'00" - E15°18'00"
Secondary Affiliation: Academy of Sciences of the Czech Republic, Institute of Physics, CZE, Czech Republic
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, copyright, Schweizerbart'sche Verlagsbuchhandlung. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201051
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