On the symmetry of wulfenite (Pb[MoO4]) from Mežica (Slovenia)

Abstract

Wulfenite [lead(II) molybdate(VI)] is known as a scheelite structure in the I41/a space group. The structure of the unusual hemimorphic wulfenite crystals from the Meica mine was refined in the noncentrosymmetric space group I using a Pb/Mo exchange disorder model with the approximate com-position Pb 0.94Mo0.06[MoO4]. Pb atoms in the 2b positions are substituted by Mo at about 12%. The crystal is shown to be twinned by inversion. Hemimorphism may result from the short-range chemical ordering of the metal atoms at the 2b positions. © 2011 International Union of Crystallography.