The crystal structure of angelaite Cu2AgPbBiS4

TY - JOUR

T1 - The crystal structure of angelaite Cu2AgPbBiS4

AU - Topa, D.

AU - Makovicky, Emil

AU - Putz, H.

PY - 2010/2

Y1 - 2010/2

N2 - The crystal structure of angelaite, ideally Cu2AgPbBiS 4, a 12.734(5), b 4.032(1), c 14.633(5) Å, V751.2(5) Å3, space group Pnma, Z = 4, Dcalc = 6.89 g.cm -3, from the Ángela mine, Los Manantiales district, province of Chubut, Argentina, has been solved by direct methods and refined to R 1 = 6.47% on the basis of 606 unique reflections [F0 > 4σ(F0)]; these were collected on a Bruker P3 diffractometer with a CCD detector and MoKa radiation from a fragment consisting of an intergrowth of angelaite and galena. Angelaite contains a capped trigonal prismatic Pb site, a quasi-octahedral Bi site, a linearly coordinated Cu site, and three triangular sites, one occupied by Ag and two partially occupied by Cu. Angelaite is a homeotype of galenobismutite with the Pb and Bi1 sites of galenobismutite preserved, and the Bi2 site replaced by the combination of Ag and Cu sites described above, which represent a novel type of substitution: (Ag+ + 2Cu+)-for-Bi3+. Selenium-free galenobismutite from Felbertal (Austria) was refined to the R1 value of 2.49% to serve as a reference structure related to that of angelaite.

AB - The crystal structure of angelaite, ideally Cu2AgPbBiS 4, a 12.734(5), b 4.032(1), c 14.633(5) Å, V751.2(5) Å3, space group Pnma, Z = 4, Dcalc = 6.89 g.cm -3, from the Ángela mine, Los Manantiales district, province of Chubut, Argentina, has been solved by direct methods and refined to R 1 = 6.47% on the basis of 606 unique reflections [F0 > 4σ(F0)]; these were collected on a Bruker P3 diffractometer with a CCD detector and MoKa radiation from a fragment consisting of an intergrowth of angelaite and galena. Angelaite contains a capped trigonal prismatic Pb site, a quasi-octahedral Bi site, a linearly coordinated Cu site, and three triangular sites, one occupied by Ag and two partially occupied by Cu. Angelaite is a homeotype of galenobismutite with the Pb and Bi1 sites of galenobismutite preserved, and the Bi2 site replaced by the combination of Ag and Cu sites described above, which represent a novel type of substitution: (Ag+ + 2Cu+)-for-Bi3+. Selenium-free galenobismutite from Felbertal (Austria) was refined to the R1 value of 2.49% to serve as a reference structure related to that of angelaite.

M3 - Journal article

SN - 0008-4476

VL - 48

SP - 145

EP - 153

JO - Canadian Mineralogist

JF - Canadian Mineralogist

IS - 1

ER -