Ceramics-Silikáty 52 (1) 49-53 (2008)

NATURAL Pb₉Sb₈S₂₁ FROM KUTNÁ HORA, FIRST OCCURRENCE, CHEMISTRY AND X-RAY POWDER DIFFRACTION DATA

R. Pažout

Natural Pb₉Sb₈S₂₁, known as the mineral semseyite, was newly identified in the Kutná Hora ore district, Central Bohemia, Czech Republic. Chemical compositional data and X-ray powder diffraction data are presented in the paper. Chemical composition was determined by electron microprobe analysis which revealed increased content of Bi and Se. Unit cell para-meters have been calculated. Semseyite has a monoclinic unit cell with a = 13.626(18), b = 11.960(12), c = 24.325 (45), β = 105.83 (11), V = 3813.96 A3, space group C2/c. Lenghtening of a and b parameters compared to the published structure is accompanied by shortening of the c parameter reflecting the actual chemical composition.

Keywords: Chalcogenides, Pb-Sb sulphosalts, Natural Pb₉Sb₈S₂₁, Semseyite