crystallographic analysis of microtwin STRUCTURES of sulfides: the case study of lillianite and HEYROVSKYITE
S. V. Borisov, S. A. Magarill, N. V. Pervukhina
Keywords: microtwining, lillianite, heyrovskyite, sulfides, sulfosalts, tablet structures, structure-determining factors, cation and anion sublattices, building blocks, crystallographic analysis
Pages: 744-750
Abstract
Crystal structures of the minerals lillianite Pb3Bi2S6 and heyrovskyite Pb6Bi2S9 are subjected to crystallographic analysis to demonstrate that the microtwinning of the structure-forming 2D layer fragments occurs within common cation and anion matrices. A combination of the PbS-type structural fragments with different orientations is achieved by vacant sites in the cation and anion translational sublattices without their noticeable distortion. In the structure of β-Pb3Bi2S6 (the high-pressure phase of lillianite), the pseudo-translational ordering of cations and anions as well as the overall symmetry of the structure are significantly lowered, while the general arrangement is preserved.
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