X-ray data for CH3OSSOCH3 were collected at -158 degrees C to determine the solid-state molecular structure and the electron density (ED). Crystal data : a = 7.151(4), b = 4.306(4), c = 9.316(2) Angstrom A; alpha = 98.37(1)degrees, beta = 100.00(2)degrees, gamma = 92.11(1)degrees, space group P $($) over bar$$ 1, Z = 2. Multipole refinements were carried out to obtain a model for the static charge distribution. The results are compared with ab initio HF calculations at the 6-31G(**) level. The molecular structure in the solid state deviates slightly from C-2 symmetry. Molecular parameters averaged for C-2 symmetry : d(SS) = 1.972(1), d(SO) = 1.658(4), d(CO) = 1.435(1) Angstrom A; alpha(COS) = 114.5(1)degrees, alpha(OSS) = 108.2(1)degrees, tau(SS) = 81.5(1)degrees, tau(SO) = 75(3)degrees. The experimental deformation ED shows considerable differences for the two S-O bonds and in the nonbonded areas of the S and O atoms. The directional characteristics of these lone-pair deformations are in accord with the crystal packing, and thus, they can be correlated with the electrostatic S-O intermolecular interactions.