All ten of the binary and mixed trihalogeno-complexes of tin(l1).[SnXYZ] -(X, Y, or Z = CI, Br, or I), have been prepared as salts of one or more of the cations [Et,N]+, [Bun,N]+, and [Ph,As]+.Their far4.r. (to 80 cm-l) and Raman spectra show that discrete pyramidal trihalogeno-anions are present in solution. This structure is retained in the solid state for the [Bu",N]+ salts, but with [Ph,As]+ and [Et,N]+ cations there is increasing solid-state interaction resulting in a lowering of symmetry. This is shown also by the WSn Mossbauer data. For salts of a given cation, the isomer shifts show a regular variation with the sums of the electronegativities of the halide ligands. Quadrupole splitting was observed in each case, and showed an inverse relationship to the isomer shifts in each series ; this is most readily interpreted as a consequence of a quadrupole splitting-electronegativity correlation.The species absorbed by an anion-exchange resin in the halide (X-or Y-) form from SnX,-HX solutions (X or Y = CI, Br, or I) are shown to be [SnXJ-or [SnX,Y]-, and not [SnX,I2-as previously reported for X = CI.PREVIOUS studies on trifluorostannates(11) have indicated that with some cations, anion-association takes place in the solid state.lP2 With tribromo-and tri-iodostannates(I1) the vibrational spectra show that with such large cations as [Ph,As]+ the anion is three-coordinate but has lower symmetry than C, , unlike the chloro-analogue^.^ The few data available at the commencement of this work ** suggested that the Mossbauer parameters of halogeno-anions of tin (11) are also dependent upon the cation. It was therefore of interest to investigate in more detail the influence of cations on the vibrational and Mossbauer spectra of solid trihalogenostannate(I1) salts.The cations chosen for this study were such that