Sn-119 Mossbauer spectroscopy was performed on a series of formal Sn(II) dichloride and dihydride adducts bound by either carbon- or phosphorus-based electron pair donors. Upon binding electron-withdrawing metal pentacarbonyl units to the tin centers in LB center dot SnCl2 center dot M(CO)(5) (LB = Lewis base; M = Cr or W), a significant decrease in isomer shift (IS) was noted relative to the unbound Sn(II) complexes, LB center dot SnCl2, consistent with removal of nonbonding s-electron density from tin upon forming Sn-M linkages (M = Cr and W). Interestingly, when the nature of the Lewis base in the series LB center dot SnCl2 center dot W(CO)(5) was altered, very little change in the IS values was noted, implying that the LB-Sn bonds were constructed with tin-based orbitals of large p-character (as supported by prior theoretical studies). In addition, variable temperature Mossbauer measurements were used to determine the mean displacement of the tin atoms in the solid state, a parameter that can be correlated with the degree of covalent bonding involving tin in these species.