OO en 
Chemistry. — “Notes on Cobaltammines’. By Ni Ratan Duar. 
(Communicated by Prof. Erxst Coues). 
(Communicated at the meeting of November 29. 1919). 
In two previons investigations (Zeit. Anorg. Chem. 1913, 80, 43; 
84, 224) | had occasion to study certain proporties of the cobalt- 
ammines. This note is the result of the continuation of my previous 
work. 
1. Let us pof ip slollo wane series of compounds _ 
‘ 3 NH), (NH), (NH), 
> 1 CI E / 
[Co (NH,),] Cl, , | 0 aa CL, [co plea Ne [eo Ae | 
K | Co 50) el and K, [Co (NO Det: For the preparation of 
NN _ (NA), NHJ. _ (NED, 
Er NO, je [ee nis BL [ee SO.) ql ie jee on 
the general meihod of procedure is to mix a cobalt salt, ammonium 
chloride, ammonium hydroxide and a nitrite; by this a complex 
cobaltous compound is formed which is turned into the stable cobaltic 
compound by oxidation. The amount of a certain compound which 
will be formed, depends on the concentration of the reacting substances 
and on the solnbility of the resulting complex compound. If the 
concentration of the nitrite in the solution is large in comparison 
with the concentrations of ammonium hydroxide and ammonium 
chloride. we should expect that several (NO,) groups would enter 
the complex. 
It bas been known from a long time that aquopentammine salts 
can be converted into the corresponding hexammine salts by heating 
the aquo compound with ammonia in a sealed tube or in a bottle 
under pressure. 
| ad u: 
I found that if | Co ** | Cl, is warmed with a dilute solution 
(NO,) 
(NH), 
den which 
of sodium or potassium nitrite, we get mainly | co 
could be purified by reerystallisation. 
NH), 
In a similar way croceo cobalt chloride | co (NO,), 
Ja can be 
ond hast) enn 
—— Te a a ye Venn 
