1901 - 2 .] Action of Silver Salts on Ammonium Persulphate. 93 
ions would probably not be very considerable until the greater 
portion of the persulphate had been decomposed, owing to the 
considerable quantity of neutral salt present ; so that the former 
equation ( b ) might perhaps be replaced by the following one — 
(V) NH 4 * + 4S 2 0 8 + 3H 2 0 = 2H' + 8HSO/ + NOf 
While the results of the experiments are in some respects in- 
complete and inconclusive, there seems little doubt that the speed 
of the reaction is determined by the formation of silver peroxide, 
the oxidation of the ammonium ions taking place much more 
rapidly. 
It has been assumed that silver peroxide is actually formed in 
the above decompositions, but another, and, on the whole, prefer- 
able hypothesis is possible. Silver peroxide has never been 
prepared quite pure, and its exact nature is somewhat doubtful. 
When prepared from silver nitrate it cannot be obtained free from 
nitrate ; it dissolves in nitric acid, and can be reprecipitated from 
the solution. It is therefore permissible to assume that silver 
peroxide is really an exceedingly feebly basic oxide, whose salts 
are hydrolysed with great ease. If we make the assumption, which 
involves the possible existence of perargentic ions (‘ diargention ’) in 
minute quantity, the interaction of persulphates and silver salts 
may be represented as follows — 
(c) 2Ag+S 2 0 8 "-== 2Ag" + 2S0 4 ". 
In absence of oxidisable substances hydrolysis takes place, with 
separation of perargentic hydroxide, oxide, or basic salt. In 
presence of ammonium ions, however, the formation of nitric acid 
takes place, with £ reduction 5 of the perargentic ions as follows — 
(d') 8Ag” + KH/ + 3H 2 0 8Ag* + 10ET + N0 8 \ 
{Issued separately March 31 , 1902 .) 
