THE CRYSTAL-STRUCTURE OF JANKOVICITE, TL5SB9(AS,SB)4S22

The recently discovered mineral jankovicite with the formula Tl5Sb9(As ,Sb)4S22 from the Allchar region, Macedonia, was investigated by singl e crystal X-ray diffraction methods. The structure was determined by d irect methods from 3502 reflections, measured on a four-circle diffrac tometer, and refined to a final R-value of R/R(w) = 0.062/0.038. The c ell parameters are a0 = 7.393(4) angstrom, b0 = 8.711(5) angstrom, c0 = 17.58(1) angstrom, alpha = 103.81(3)degrees, beta = 91.81(3)-degrees , gamma = 109.51(3)-degrees; space group P1, Z = 1. The structure cons ists of kinked chains of SbS(n) (n = 3, 2 + 2, 3 + 1, 3 + 2, 3 + 3) po lyhedra //c which are connected by AsS3 pyramids to form puckered laye rs // (100). These Sb-As-S layers are interconnected via Tl atoms in e ight coordination. One Tl atom and one Sb atom share an approximately common site which is statistically occupied. The As sites are partiall y substituted by Sb. The structure shows close similarities with that of rebulite, Tl5Sb5As8S22.