Reinvestigation of the crystal structure of lautite, CuAsS

Abstract

The crystal structure of the mineral lautite (copper arsenic sulfide), CuAsS, previously described as either centrosymmetric [Pnma; Marumo & Nowacki (1964). Schweiz. Miner. Petro. Mitt. 44, 439-454] or noncentrosymmetric [Pna21; Craig & Stephenson (1965). Acta Cryst. 19, 543-547], was reinvestigated by means of single-crystal X-ray diffraction. The centrosymmetric structural model reported previously was confirmed, although with improved precision for the atomic coordinates and inter-atomic distances. Lautite shows a sphalerite-derivative structure with a linking of Cu[AsS3], As[CuAs2S] and S[Cu3As] tetra-hedra. All atoms lie on special positions (Wyckoff position 4c, site symmetry m).