Proudite from Tennant Creek, Northern Territory, Australia: its crystal structure and relationship with weibullite and wittite

has a known range of solid solution expressed by the general formula Cu,Pbr.uBir..r-o tt' (S", Se'-r)rr, where 0.04 ( x ( 0.98 and 0.57 ( y< 0.82. Single-crystal X-ray data were collected using the integrating Weissenberg equi-inclination method with multiple film packs; and the structure was solved by the Patterson method and refined by a least-squares procedure to give a final R of 0.17. The asymmetric unit contains 8 Pb, 10 Bi, I Cu, and 23 S atom sites. The Cu site, one Bi, and two S sites are partially occupied and the solid solution Pb?.sBie 6? (S,Se)r, c CuPb, uBir.rs(S,Se)2, probably exists. Pb and Bi atoms may be distinguished with only a moderate degree of confidence on the basis of differences in their bonding geometry; the selenium is preferentially ordered into seven of the anion lattice sites. The structure of proudite is closely related to that of junoite, CurPbrBL(S,Se),,, the other main selenium-rich mineral intergrown with proudite at Juno. This study also incorporates new X-ray and chemical data on the little studied seleniferous ulphosalts wittite and weibullite, and proves that all three are distinct mineral species. Zoning of bismuth-rich sulphosalts in the ore bodies at Juno is discussed