Acta Crystallographica Section B

Structural Science

Volume 68, Part 5 (October 2012)


research papers



Acta Cryst. (2012). B68, 480-492    [ doi:10.1107/S0108768112034027 ]

Comparative modular analysis of two complex sulfosalt structures: sterryite, Cu(Ag,Cu)3Pb19(Sb,As)22(As-As)S56, and parasterryite, Ag4Pb20(Sb,As)24S58

Y. Moëlo, C. Guillot-Deudon, M. Evain, P. Orlandi and C. Biagioni

Abstract: The crystal structures of two very close, but distinct complex minerals of the lead sulfosalt group have been solved: sterryite, Cu(Ag,Cu)3Pb19(Sb,As)22(As-As)S56, and parasterryite, Ag4Pb20(Sb,As)24S58. They are analyzed and compared according to modular analysis. The fundamental building block is a complex column centred on a Pb6S12 triangular prismatic core, with two additional long and short arms. The main chemical and topological differences relate to the short arm, which induces a relative a/4 shift (~ 2 Å along the elongation parameter) of the constitutive rod layers, as illustrated by distinct cell settings within the same space group (P21/n and P21/c, respectively). Selection of the shortest (i.e. strongest) (Sb,As)-S bonds permitted to enhance the polymeric organization of (Sb,As) atoms with triangular pyramidal coordination. These two quasi-homeotypic structures are expanded derivatives of owyheeite, Ag3Pb10Sb11S28. The hierarchy of organization levels from zero- to three-dimensional entities is subordinated to building operators, which appear as the driving force for the construction of such complex structures. Minor cations (Ag, Cu) or the As-As pair in sterryite secure the final locking, which favours the formation of one or the other compound.

Keywords: modular analysis; complex sulfosalt structures; sterryite; parasterryite; owyheeite derivative.


hkldisplay filedownload file

Structure factor file (CIF format) (1086.6 kbytes)
[ doi:10.1107/S0108768112034027/bp5041sterryitesup2.hkl ]
Contains datablock sterryite


hkldisplay filedownload file

Structure factor file (CIF format) (1726.3 kbytes)
[ doi:10.1107/S0108768112034027/bp5041parasterryitesup3.hkl ]
Contains datablock parasterryite


Notes:

To open or display or play some files, you may need to set your browser up to use the appropriate software. See the full list of file types for an explanation of the different file types and their related mime types and, where available links to sites from where the appropriate software may be obtained.

The download button will force most browsers to prompt for a file name to store the data on your hard disk.

Where possible, images are represented by thumbnails.

 bibliographic record in  format

  Find reference:   Volume   Page   
  Search:     From   to      Advanced search

Copyright © International Union of Crystallography
IUCr Webmaster