The structures of ZrNCl, TiOCl and AlOCl in the light of the Zintl-Klemm concept

Abstract

Abstract The structures of ZrNCl on one hand and TiOCl and AlOCl on the other hand are analysed in comparison with the Zintl phases Ca[Al2Si2] and Na[AlSi], respectively. In the former, the [ZrN]+ sublattice is isostructural to the [Al2Si2]2- skeleton whereas the latter are orthorhombic distortions of the Na[AlSi] structure. The three structures can be rationalised by means of an inverse Zintl-Klemm concept, in similarity with the Zintl-Klemm concept which accounts for the structures of the Zintl phases. In addition, Ca[Al2Si2] presents the same structure than the hexacelsian oxide Ca[Al2Si2O8] providing a new example of how the cation arrays, in oxides, maintain the structure of their respective alloy.