The P43 enanti-omorph of Sr2As2O7.
The crystal structure of strontium diarsenate has been reinvestigated from single-crystal X-ray diffraction data. In contrast to the previous determinations of this structure [Weil et al. (2009 ▶). Solid State Sci. 11, 2111-2117; Edhokkar et al. (2012 ▶). Mater. Sci. Eng., 28, 012017] and to all isotypic A 2 B 2O7 compounds that crystallize in the space group P41, the current redetermination revealed the P43 enanti-omorph of Sr2As2O7 with a purity of 96.3 (8)%. The crystal structure is made up from two eclipsed As2O7 diarsenate groups (symmetry 1) with characteristically longer As-O bridging bonds [1.756 (4)-1.781 (4) Å] than the terminal As-O bonds [1.636 (4)-1.679 (4) Å] and four Sr(2+) sites with coordination numbers ranging from seven to nine. The building units are arranged in sheets parallel to (001).
Laboratoire de Chimie Industrielle, Département de Génie des Matériaux, Ecole Nationale d'Ingénieurs de Sfax Université de Sfax, BP W3038, Sfax, Tunisia.
Aicha
A
Mbarek
Laboratoire de l'Etat Solide, Faculté des Sciences, Université de Sfax, BP W3038, Sfax, Tunisia.
Fadhila
F
Edhokkar