Original paper

Contributions to the crystal chemistry of thallium sulfosalts. IV. Modular description of Tl-As-Sb sulfosalts rebulite and jankovicite

Makovicky, E.; Balić-Žunić, Tonči

Neues Jahrbuch für Mineralogie - Abhandlungen Band 174 Heft 2 (1998), p. 181 - 210

19 references

published: Oct 20, 1998

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ArtNo. ESP154017402004, Price: 29.00 €

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Abstract

On modular level the crystal structures of Tl-As-Sb sulfosalts jankovicite (Libowitzky et al. 1995) and rebulite (Balić-Žunić et al. 1982) are composed of (210) layers of SnS archetype, alternatively one and two coordination pyramids thick. These layers are joined by layers with mirror symmetry which contain Sb/As pyramids and TIS8 cubes. Variable thickness of SnS-like layers yields hypothetical homologous series. Periodic twinning of SnS-like layers on (101)SnS alters the jankovicite structure into the rebulite structure. This twinning does not have OD character. The OD layers (100) of jankovicite have idealized symmetry A (1) 2/m 1, interlayer elements are {(1) 21/2a2 1}. Besides the observed polytype P1 another maximally ordered variant, A 2/m is possible. It remains unobserved, probably due to desymmetrization of OD layers. The complex rings and spirals of BS3 and BS4 polyhedra (B = As, Sb) are centered on SnS-like layers. They are not vehicles for accommodation of ione electron pairs.

Keywords

crystal structuresTl-As-Sb sulfosaltspolyhedraione electron pairs