Tracer investigations of the fate of sulphur atoms in the course of high-temperature reactions

The fact that sulphur occurs in many different chemical conditions suggests a number of interesting problems in connexion with the movement of the sulphur atoms in the course of reactions between different compounds of this element. Quite an amount of information is available concerning reactions between compounds of sulphur in solution and, in general, the different sulphur fractions do not mix under these conditions. An entirely different situation is found in reactions between gases and solid compounds. For these processes much higher temperatures are, in general, required and at these higher temperatures the sulphur atoms in the different fractions tend to mix to a very large extent. This behaviour is illustrated by means of data obtained on the exchange of radiosulphur between sulphur vapour and sulphur dioxide, between sulphur dioxide and solid sulphite and between sulphur dioxide and solid sulphate. The same behaviour has been observed in the chemical decomposition of thiosulphate, labelled in one of the two sulphur fractions and in the oxidation of this compound. Finally, it has been shown that mixing is also very strong in the reaction between sulphur vapour- and solid sulphate. (author)