The liquid range of fluorosulphates

Abstract

The increase in boiling point caused by insertion of sulphur trioxide into fluorides is almost linearly related to the molecular-weight ratio of fluoride to fluorosulphate. The lighter the fluoride the greater the increase in liquid range; HSO₃F is the limiting member of the fluorosulphate series. Insertion of a second sulphur trioxide unit causes a smaller proportionate increase. Positive deviations with liquids are encountered when the fluorosulphate is more associated than the fluoride and vice versa. Positive deviations with solids, which appear when salts are formed, confirm the ionicity of ClO₂⁺SO₃F^– and SbCl₄⁺SO₃F^–. The predictive value of these correlations is illustrated.