The crystal structure of marrite, PbAgAsS3

Abstract

Marrite, a rare sulfosalt from the Binnatal, Switzerland, has been shown to have composition PbAgAsSa. The phase is monoclinic, space group P 21/a, with a = 7.2705, b = 12.6319, c = 5.9853 A, fJ = 91 ° 13.7'. The structure is a super. structure based upon a PbS-like arrangement of atoms. The structure was solved through systematic consideration of all possible arrangements permitted by the subcell.supercell relationship. Refinement was carried to R = 10.9%' a valuo which was shown to represent a limit imposed by reliability of the data.