The electron contact densities for the various electron configurations of tin and its oxidation states have been computed using the relativistic multi-configuration Dirac-Fock program of Desclaux (1975). The interactions between the configurational states obtained using jj-coupling and the seniority scheme have been investigated using Grant's program (1976) MCP75. All the off-diagonal matrix elements of the inter-electronic Coulomb interaction between the configurational states are found to be vanishingly small. The dependence of the computed electron contact density on the valence shell occupation numbers has been investigated and a phenomenological formula obtained. Using the formula and the measured Mossbauer isomer shift, the electron configuration of beta -tin has been found to be 5s^1.785p^2.22 in good agreement with the literature value.