Original paper
The crystal structure of Cu2Pb6Bi8S19
Topa, Dan; Makovicky, Emil; Balić-Žunić, Tonči; Berlepsch, Peter
European Journal of Mineralogy Volume 12 Number 4 (2000), p. 825 - 833
12 references
published: Jul 17, 2000
manuscript accepted: Mar 9, 2000
manuscript received: Sep 27, 1999
Abstract
Abstract The crystal structure of natural Cu2Pb6Bi8S19, space group C2/m, a = 27.64 Å, b = 4.05 Å, c = 20.74 Å, β= 131.26°, has been determined and refined to the value of R = 0.05 from 1488 reflections with I> 2 σI obtained on four-circle diffractometer equipped with a CCD area detector. It is composed of en echelon staggered fragments of (100)PbS sulfide layers which are two atomic layers thick and alternate with periodically sheared (111)Pbs layers; these are two octahedra thick. It is built from Pb coordination octahedra and bicapped trigonal prisms combined with Bi in square pyramidal/asymmetric octahedral coordinations. Cu occurs in paired tetrahedra interconnecting the staggered (100)Pbs fragments. Cu2Pb6Bi8S19 forms a homologous series with Cu2Pb3Bi8(S, Se)16 Gunoite) in which the sheared (111)Pbs layers are one octahedron thick. CU2Pb6Bi8S19 is a new sulfosalt from Felbertal, Austria
Keywords
CU2Pb6Bi8S19 • crystal structure • homologous series • junoite • sulfosalt