Struktur-Analyse des Bournonits und Seligmannits mit Hilfe der Superpositions-Methoden

Abstract

During the course of the structure analyses the space group D 2 h 13 - Pnmm assumed by O ftedahl (1932) and F rondel (1941) had to be forsaken in favour of the hemihedral space group C 2 v 7 – Pn 2 m . The structures were deduced from the P atterson diagrams by means of the superposition method. The x -and z -parameters were refined step by step by F ourier syntheses. The y -parameter derived from the superpositions had to be corrected by trial and error. Other methods used during the investigation are shortly discussed. Apart from slight differences in parameters both minerals have identical structures and show very close relationship to the analogous Bi -compound aikinite and also to stibnite Sb 2 S 3 .