Heats of formation of sulphuryl chlorofluoride and lead chlorofluoride

Abstract

Standard heats of formation of PbCIF and SO₂CIF have been determined from heats of precipitation and hydrolysis respectively. The enthalpy of PbCIF is more negative than the mean of the corresponding difluoride and dichloride, whereas the opposite is true for SO₂CIF. These results can be used to controvert the claim that reaction of PbF₂ with SO₂Cl₂ produces SO₂CIF exclusively. Heats of formation of SO₂Br₂, SO₂BrF, and HSO₃Br have been estimated and shown to be compatible with their formation and decomposition modes. An explanation is given for the partial hydrolysis of SO₂F₂ as compared with the complete hydrolysis of SO₂CIF.