rOTASSIUM NITKITO-HYDROXIMIDOSULPHATES. 215 



separates. If now to this fluffy matter suspended in its cold 

 mother-liquor carefully decanted from every particle of the crys- 

 tals of the '3/6 normal salt a liot solution of this 5/() normal salt 

 in 50 or even 40 per cent, nitrite be poured in, a relatively large 

 quantity of the fluffy matter is obtained and not the hard 

 prisms of the 5/6 normal salt. Under the microscope the fluffy 

 matter proves to be crystalline and when drained on the tile it 

 exhibits a silvery lustre while on analysis it proves to be the 

 nitrito-2/3 normal hydroximidosulphate only slightly impure from 

 the presence of a little 5/6 normal hydroximidosulphate and nitrite. 

 Thus in place of the potassium 33.10 and sulphur 18.06 per cent, 

 we found in it 33.79 and 18.35 respectively, together with an 

 alkalinity equal to 1.09 per cent, potassium. Dissolved up in 

 hot 12 per cent, nitrite solution it recrystallises as the pure 

 double salt. It is thus apparent that in a very concentrated 

 solution of nitrite containing the ojß normal salt dissolved there is 

 unstable equilibrium between tlie tendency to yield HON (SO;; K).^, 

 KON(SO,K)2,OH2 again and that to form HON (SOo K),, 

 KONO. 



Sodium nitrite forms a compound with sodium 2/3 normal 

 hydroximidosulphate which has not been further examined prin- 

 cipally because of its high solubility in sodium-nitrite solution. 



Potassium nitrite and normal hydroximidosul'phate KNOo, 

 2K0N(S0oK)., 40Ho.— This compound salt is only obtainable 

 from a strongly alkaline solution. For when the normal hydrox- 

 imidosulphate is dissolved in a hot concentrated solution of the 

 nitrite only the h\'6 normal hydroximidosulphate crystallises out 

 on cooling just as it would do in the absence of nitrite. In 

 order to crystallise out either the normal hydroximidosulphate 

 (this Journal, 7, 30) or its combination with nitrite free alkali 



