Nonrelativistic and quasirelativistic SCF-MS calculations on the diphenyltin(IV) dichloride monomer and possible “dimer”, give theoretical insight into the intermolecular chlorine interaction. This molecule is not a polymer like other diorganotin(IV) dichlorides. A weak interaction occurs in the valence orbital electronic structure; the extent of the interaction is given by the molecular one-electron properties. The isomer shift and the quadrupole splitting of the Mössbauer active 119Sn, and the nuclear quadrupole resonance (n.q.r.) frequency of 35Cl are properties which are helpful in analysing the extent of intermolecular interaction in the “dimer”. The calculated isomer shift and quadrupole splitting agree with experiment. The n.q.r. frequency of 35Cl does not agree well with experiment, which is not a single crystal measurement, but nevertheless the weakness of the intermolecular chlorine interaction was confirmed. Further confirmation comes from the total density plot of (Ph 2SnCl 2) 2.