A tin-119 Mossbauer spectroscopic investigation of some chalcogen-containing Zintl phases

The Sn-119 Mossbauer parameters for some chalcogen-containing Zintl phases of composition M4SnX4 (M = Na, K; X = S, Se, Te), Na2SnSe3, M3SnTe3 (M = K, Rb, Ca), Cs4Sn2Te7 and M2SnTe5 (M = K, Rb) are reported. All the compounds contain tetrahedrally coordinated tin and the chemical isomer shift data s how the tin to be involved in covalent bonding with the chalcogen atoms. Th e dependence of the Sn-119 Mossbauer parameters on the local coordination o f tin, the extent of polymerisation of the anionic sub units, the transfer of electrons from the alkali metal to the anionic units, and the electroneg ativity of the chalcogen atoms are discussed. (C) 1999 Elsevier Science Ltd . All rights reserved.