IMIDOSTJLPHOJSATES (2ND. PAPER). 205 



Lead imidosulphonales. 



We have indicated the existence of an unstable salt. PbHNS 2 6 , 

 in solution, and Berglund has done the same. 



The crystalline, normal hydroxy-lead imidosulphonate, described 

 by us, (HOPb) : .,XS,O ti . has also been described by him, and our 

 accounts agree. But his way of preparing- it was to add ammo- 

 nia gradually to mixed solutions of diammonium imidosulphonate and 

 lead acetate so long as the amorphous precipitate it at once produces 

 gives place to a crystalline one. When the last-formed amorphous 

 precipitate does not disappear, addition of ammonia is exchanged for 

 that of acetic acid until it has just been converted to the crystalline 

 precipitate. 



The amorphous precipitate obtained by the use of ammonia in 

 excess and by using basic lead acetate he found to be a basic compound 

 of varying composition. It is the lead salt which Jacquelain seems to 

 have used for the isolation of imidosulphonic acid. We have shown 

 in our first paper (6 90) that a basic lead imidosulphonate can be 

 uniformly obtained of the composition. (HO) 5 Pb 4 NS 2 6 . 



Silver imidosulphonates. 



Berglund has described only the normal silver salt. We have 

 described this and two other, crystalline, well-characterised salts, 

 Ag 2 NaNS 2 G and AgNa 2 NS 2 6 , the latter obtained Avhen silver nitrate 

 is added to excess of normal sodium imidosulphonate, circumstances in 

 which, according to Berglund, a precipitate forms that is richer in 

 silver than the normal argentic salt. This apparently strange result is 

 explicable through the fact that he worked with highly dilute solutions, 

 for as we have pointed out (6, 95), the salt AgN"a 2 NS 2 6 is partly 



