CoCl3.nNH3
Composition Color No. Cl- Formula
CoCl3.6NH3 yellow 3 [Co(NH3)6]Cl3
CoCl3.5NH3 purple 2 [Co(NH3)5Cl]Cl2
CoCl3.4NH3 green 1 [Co(NH3)4Cl2]Cl
CoCl3.4NH3 violet 1 [Co(NH3)4Cl2]Cl
The green and violet compounds must have some further difference.
All have 6 ligands (coordination number = 6)