517 
(NH). 
- - - - - - 4 
converted into | co ] by warming it with a dilute solution of 
(NO). 
v ; NH 
a nitrite, whilst | co al can be converted into K [co aM 
(NH), 
by warming | co ] with a concentrated solution of potassium 
(NO), 
nitrite, ammonia escaping from the solution. 
N 
I tried to prepare the compound K, ‚| Co ae 
(NH). 
(NO), 
} which is still 
anknown, by warming K| co, Al with potassium nitrite, but was 
unsuccessful. 
en 
__ On the other hand, one can convert K| Co Seale into | co 0 
and | co Se nto | co San Cl by warming the compound in 
question with a mixture of ammonium chloride and ammonium 
hydroxide. 
In all these cases, ammonium salts are used along with ammonium 
hydroxide, and their function is to suppress the ionisation of the 
base and form undissociated NH,OH, which is in equilibrium with 
NH,. The NH, then enters into the complex molecule. 
2. If a fairly concentrated solution of aqnopentammine cobaltie 
chloride [corn a)s 
4 oe is left, it slowly gives a precipitate of the 
eorresponding purpureo salt [co ea | Cl, 
NAL), SE) 
[co Cl) Je + H,0 =| Co (1.0) Je 
This is a case of equilibrium in solution and the purpureo salt 
being much less soluble comes out as a precipitate. 
If we start with a solution of purpureo cobalt chloride | co pen Je. 
and add ammonium hydroxide and warm the mixture, we get the 
(NH), 
method of preparation of the aqno salt. 
I find that the ammonium hydroxide has only a catalytic effect 
on the hydrolysis of the purpureo salt into the aquopentammine salt. 
A solution of the purpureo chloride takes up a molecule of water 
aquopentammine salt [co ‘Je. in solution, and this is the usual 
