Dissolve 6 g of ammonium chloride in 40 mL of conc. ammonia with stirring and then add 12 g of cobalt chloride hexahydrate. Then slowly add 10 mL of 30% hydrogen peroxide and then slowly add 30 mL of conc. HCl. Heat in 85°C with stirring for 20 minutes and then allow to cool slowly at room temp, then put the mixture into a freezer and filter the mixture. Wash the product with some ice cold water and dry at 90°C.
4 CoCl2 + 4 NH4Cl + 16 NH3 + 2 H2O2 + 6 H2O = 4 [Co(NH3)5Cl]Cl2 + O2
Stirring the hot mixture
The dry product