A number of both mono and bis addition compounds of dimethyl- and diphenyltin dichloride with oxygen donor molecules of the general type RnEO (E = C, N, P, S) have been prepared and characterized by Mössbauer, infrared, and Raman spectroscopies. In the solid state the bis derivatives all have trans methyl or phenyl groups, and with the sole exception of Me2SnCl2•2C5H5NO, all appear to have cis-chlorines and cis-donor molecules. Considerable distortions of the Ph2Sn groups from linearity are suggested. The rather unusual R2SnCl2•L complexes appear to have trigonal bipyramidal structures in which the R groups and one Cl atom occupy equatorial positions, with the donor molecule and second Cl atom in apical positions. Again the C5H5NO adduct of Me2SnCl2 seems to be an exception, with both apices apparently occupied by Cl atoms.