Crystal structure of the solid solution (Sr1.65Pb0.35)Al6O11

Abstract

The title compound, di(strontium/lead) hexaaluminate, is a member of the solid solution series (Sr2-xPbx)Al6O11. It contains two statistically occupiedM2+(M= Sr, Pb) sites [both with site symmetries ..m; Sr:Pb occupancy ratios = 0.756 (2):0.244 (2) and 0.8968 (19):0.1032 (19)] that are located in the voids of an aluminate framework. TheM2+sites are surrounded by six and seven O atoms, respectively, if a cut-offM—O distance of 3 Å is chosen, resulting in considerably distortedMOxpolyhedra. The aluminate framework consists of three AlO6octahedra (two with point-group symmetries ..2/mand one with ..2) sharing edges to form partially filled layers extending parallel to (100) and located atx= 0, 0.5. Adjacent AlO6layers are linked by a network made up from two crystallographically different AlO4tetrahedra by sharing corners.