The Mössbauer effect in tin(II) compounds. Part XIII. Data for the products from molten caesium–tin(II)–halide systems

Abstract

The ¹¹⁹Sn Mössbauer parameters and the X-ray diffraction powder data for the products obtained from the molten mixed halide systems CsSnX₃–CsSnX′₃(X and X′= F^–, Cl^–, Br^–, and I^–) are reported. The nature of the solidus–liquidus curves for these systems and the colours of the mixtures at the melting points, suggest that every phase has a cubic high-temperature modification. Two types of product are obtained from the cooled melts (i) complexes containing tris(ligand)stannate(II) species and (ii) compositions which have cubic or near cubic unit cells based on the perovskite lattice. The Mössbauer data for the latter materials are characterised by relatively high chemical shifts and narrow line widths which suggest that the tin (II) is in a regular octahedral environment. Even the presence of F^– in the CsSnBr₃ and CsSnl₃ lattices does not lead to the disruption of the tin(II) bonding electrons normally associated with the presence of Sn–F bonds.