NITKILOSULPHATES. Ö 



be made to yield potassium nitrilosulphate by double decom- 

 position. 



Ammonium salt. 



Nothing haw been done concerning this interesting salt, 

 N(S0 3 NH 4 ) 3 , 20H 2 , since Fremy described it, but as its existence 

 lias been ignored since the time of the publication of its discovery 

 until now, we hold it important to again introduce some account 

 of it, derived from Fremy's memoir {Ann. Chim. Phys., 1845, 15, 

 408) into chemical literature. In presence of a large excess of 

 ammonia a concentrated solution of ammonium nitrite is submitted 

 to the action of a current of sulphur dioxide until abundant 

 precipitation of crystals has occurred in the solution kept suffici- 

 ently cool. The washed and dried salt gave Fremy the following 

 numbers on analysis, indicating the presence of one molecule of 

 water of crystallisation : 



Since the potassium nitrilosulphate contains two mois, water, 

 it is probable that the ammonium salt contains the same, and that 

 when Fremy determined the sulphur the salt had, like the sodium 

 salt, lost some of its water during its stay in the desiccator. We 

 write, therefore, the formula of the salt, N(S0 3 NH 4 ) 3 , 20tL. 



Ammonium nitrilosulphate is in minute crystals which have 

 only a slight taste, and which are somewhat sparingly soluble in 

 water, but so much more so than the potassium salt that Fremy 

 suggested that its solution might be used as a qualitative reagent 

 for potassium salts. It is not volatilised by heat but decomposed 

 into sulphate. It is a very unstable salt, being liable in the solid 

 state to decompose (hydrolyse) suddenly with a hissing sound, 



