Dipole moments and molecular structure. Part III.—The oxychlorides of sulphur

The work described here forms part of a study of the dipole moments of simple inorganic compounds. Polarisation measurements upon thionyl chloride and sulphuryl chloride appeared to be of particular interest in view of the fact that in these compounds the oxygen-sulphur linkages must be in the nature of semi-polar double bonds, since both members of the electron pairs concerned in these linkages come from the sulphur atoms, thus: where, O and × represent electrons derived originally from the oxygen, sulphur, and chlorine atoms respectively. Consequently, it would be anticipated that these compounds might show relatively large dipole moments, and would also possess a considerable atomic polarisation. (A communication concerning the relationship between atomic polarisation and molecular structure is being published shortly.) No previous measurements of the polarisations of these compounds, either in the gaseous state or in dilute solution, appear to have been recorded.Materials . The thionyl chloride and sulphuryl chloride were prepared by fractionating the “pure” commercial products several times. The boiling points of the materials thus produced were 77° C. and 70° C. respectively. The benzene was purified as described in Part II of this series, and was dried over successive quantities of sodium wire until the latter retained its metallic lustre.