TY - JOUR

T1 - Gungerite, TlAs5Sb4S13, a new thallium sulfosalt with a complex structure containing covalent As-As bonds

AU - Kasatkin, Anatoly

AU - Plášil, Jakub

AU - Makovicky, Emil

AU - Chukanov, Nikita V.

AU - Škoda, Radek

AU - Agakhanov, Atali A.

AU - Tsyganko, Mikhail V.

PY - 2022

Y1 - 2022

N2 - Gungerite, TlAs5Sb4S13, is a new mineral from the Vorontsovskoye gold deposit in Northern Urals. It occurs in limestone breccias composed of calcite and dolomite and cemented by orpiment, pyrite, realgar, stibnite, and minor baryte and quartz. It belongs to the latest phases among sulfosalts (chiefly Tl-As-Sb ones) present in the ore. The empirical formula (based on the sum of all atoms = 23 pfu) is Tl0.99As5.29Sb3.77S12.95. The Raman spectrum exhibits bands corresponding to As-S and Sb-S stretching vibrations, and a band at 263 cm(-1) that is assigned to As-As stretching vibrations. Gungerite is bright orange with an orange streak, greasy luster, and perfect cleavage on {010}. It is translucent in thin fragments. The calculated density is 4.173 g/cm3. In reflected light, the mineral is yellowish-white with very weak bireflectance. In crossed polars, it is distinctly anisotropic but anisotropy efects are masked by strong internal reflections of bright orange color. Gungerite is orthorhombic, with the space group Pbcn. Unit-cell parameters determined from the single-crystal X-ray difraction data are as follows: a = 20.1958(3) angstrom, b = 11.5258(2) angstrom, c = 20.1430(2) angstrom, and V = 4688.74(12) Å3 (Z = 8). The crystal structure consists of doughnut-shaped (As,Sb)-S clusters, which have van der Waals contacts to most of the surroundings, and are connected to them only by sparse cation-sulfur bonds. These clusters are formed by a chelating mirror-symmetrical group, which is "stacked" on, around, and along rods of the TlS9 coordination polyhedra; these rods are oriented parallel to [010]. An individual doughnut-shaped cluster with a central TlS9 polyhedron half-inserted into it contains one As-As bond 2.449 Å long. The polar Tl rods form a chessboard arrangement with occasional stacking errors leading to twinning on (101). The large and complex structure of gungerite shows remote similarities to that of gillulyite and the rod-like structure of lorándite.

AB - Gungerite, TlAs5Sb4S13, is a new mineral from the Vorontsovskoye gold deposit in Northern Urals. It occurs in limestone breccias composed of calcite and dolomite and cemented by orpiment, pyrite, realgar, stibnite, and minor baryte and quartz. It belongs to the latest phases among sulfosalts (chiefly Tl-As-Sb ones) present in the ore. The empirical formula (based on the sum of all atoms = 23 pfu) is Tl0.99As5.29Sb3.77S12.95. The Raman spectrum exhibits bands corresponding to As-S and Sb-S stretching vibrations, and a band at 263 cm(-1) that is assigned to As-As stretching vibrations. Gungerite is bright orange with an orange streak, greasy luster, and perfect cleavage on {010}. It is translucent in thin fragments. The calculated density is 4.173 g/cm3. In reflected light, the mineral is yellowish-white with very weak bireflectance. In crossed polars, it is distinctly anisotropic but anisotropy efects are masked by strong internal reflections of bright orange color. Gungerite is orthorhombic, with the space group Pbcn. Unit-cell parameters determined from the single-crystal X-ray difraction data are as follows: a = 20.1958(3) angstrom, b = 11.5258(2) angstrom, c = 20.1430(2) angstrom, and V = 4688.74(12) Å3 (Z = 8). The crystal structure consists of doughnut-shaped (As,Sb)-S clusters, which have van der Waals contacts to most of the surroundings, and are connected to them only by sparse cation-sulfur bonds. These clusters are formed by a chelating mirror-symmetrical group, which is "stacked" on, around, and along rods of the TlS9 coordination polyhedra; these rods are oriented parallel to [010]. An individual doughnut-shaped cluster with a central TlS9 polyhedron half-inserted into it contains one As-As bond 2.449 Å long. The polar Tl rods form a chessboard arrangement with occasional stacking errors leading to twinning on (101). The large and complex structure of gungerite shows remote similarities to that of gillulyite and the rod-like structure of lorándite.

KW - Gungerite

KW - new mineral species

KW - Tl-As-Sb sulfosalt

KW - Raman spectroscopy

KW - crystal structure

KW - covalent bonds

KW - Vorontsovskoe gold deposit

KW - VORONTSOVSKOE GOLD DEPOSIT

KW - CRYSTAL-STRUCTURE

KW - NORTHERN URALS

KW - RAMAN-SPECTRA

KW - TL

KW - REALGAR

KW - TL-2(AS,SB)(8)S-13

KW - REFINEMENT

KW - GILLULYITE

KW - LORANDITE

U2 - 10.2138/am-2022-8003

DO - 10.2138/am-2022-8003

M3 - Journal article

VL - 107

SP - 1164

EP - 1173

JO - American Mineralogist

JF - American Mineralogist

SN - 0003-004X

IS - 6

ER -