Ni + 2(NH3•H2O) + (NH4)2CO3 + H2O [Ni(H2O)2(NH3)4](OH)2 + CO2
Nickel react with ammonium hydroxide, ammonium carbonate and water to produce hydroxide tetraamminediaquanickel(II) and carbon dioxide. Ammonium carbonate - concentrated solution. Ammonium hydroxide - 10% solution. The reaction takes place in a boiling solution.