100 



E. DIVERS AND T. HAGA. 



it can be heated moderately with very little change, if some sodium 

 hydroxide is present. But when such an alkaline and somewhat 

 concentrated solution is boiled, it rapidly decomposes into sulphite 

 and nitric oxide, and this the potassium salt does not do. 



It thus seems that the reversion of nitrososulphates to nitric 

 oxide and sulphite is dependent upon temperature alone and is not 

 prevented by the presence of water. It is otherwise with their decom- 

 position into nitrous oxide and sulphate, which is caused either by 

 water alone, or by elevation of temperature alone. For at the common 

 temperature they can be kept for an appai^ently indefinite time when 

 dry, but decompose in damp air or in solution, while when heated, 

 even in dry air, they generally decompose much more in this way 

 than into nitric oxide and sulphite. One exception to this is the 

 potassium-silver salt, which when heated gives only nitric oxide and 

 sulphite (Hantzsch). This fact points to the latter decomposition as 

 the primary effect of heat in all cases, and to the production of 

 sulphate and nitrous oxide as the result of interaction of nitric oxide 

 and sulphite. Potassium-silver sulphite not being readily oxidisable, 

 this interaction does not occur when potassium silver nitrososulphate 

 decomposes. 



