552 
converled iiito 
Co(NH.). 
by warming it witli a dilute solution of 
a nitrite, whilst 
fn (NH.)r 
can be converted into K 
L (NOJ.J 
L (NO,)J 
by warming 
Co 
(NH 
(NO,) 
8 . 
witli a concentrated solution of potassium 
nitrite, ammonia escaping from tlie solution. 
I tried to prepare the compound K 
(NH.: 
Co 
(NH.) 
which is still 
(NO,)J 
unknown, by warming K Co 
unsuccessful. 
On the other hand, one can couvert K 
(NO ). 
with potassium nitrite, but was 
Co *(!)(*** 
into 
Co 
(NO,)J 
L (NO,),J 
and 
Co 
into 
Co 
L (NO,).J 
L (NO,)J 
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 cobaltic 
chloride 
Co 
(H.0) 
corresponding purpureo salt 
Cl. is left, it slowly gives a precipitate of the 
(NH.) 
Co 
(Cl) J 
Cl, 
Cl, + H,o 
L (Cl) _ 
L (H.0) J 
Cl,. 
This is a case of equilibrium in solution and the purpureo salt 
being much less soluble comes out as a precipitate. 
Co Cl 
(Cl) ’ 
aud add ammonium hydroxide and warm the mixture we get the 
(NH.) 
If we start with a solution of purpureo cobalt chloride 
ld add ammonium 
aquopentammine salt 
(H.O) 
Cl, in solution and this is the usual 
method of preparation of the aquo salt. 
I ünd 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 
