Start to heat a solution of 6.4 mL of coned,
aqueous ammonia in 64 mL of water on the stirrer-hot plate.
The surface temperature of the hot plate is not critical.
While heating and stirring this solution, add 4 g of [Co(NH3)5 CL]CL2 (if 4 g of the chloropentaamminecobalt (III) chloride was not obtained in the previous experiment, adjust the reactants to the amount you obtained.)
Continue heating and stirring until the colored product dissolves. If a dark brown to black precipitate of cobalt Oxide forms, filter it off.
Cool the filtrate which should be clear solution to about 10 องศา add 2M HCL slowly while keeping the solution cold until it is just neutral to litmus.
Add 4 g of sodium nitrite followed by 4 ml of 6 M HCL.
After the solution has been in an ice bath, filter the precipitated salmon pink crystals of [Co(NH3)5 ONO] CL2 using a Buchner funnel .
Wash with 20 mL of ice water wash with 20 mL of alcohol, and then allow it to dry on the lab bench for one hour.
The product is not stable and will slowly isomerize to the nitro compound.