\(4N{H_4}OH + CuS{O_4} \to \mathop {[Cu{{(N{H_3})}_4}]}\limits_{{\rm{Deep}}\,{\rm{blue}}} \,S{O_4} + 4{H_2}O\)

\(\mathop {CuS{O_4}}\limits_{{\rm{Anhydrous}}} + 5{H_2}O \to \mathop {CuS{O_4}}\limits_{{\rm{Blue}}} .5{H_2}O\)

\(4FeC{{l}_{3}}+3N{{a}_{4}}[Fe{{(CN)}_{6}}]\to \underset{\begin{smallmatrix} 
 \text{Ferric}\,\text{ferrocyanide} \\ 
 \,\,\,\,\,\text{(Prussian}\,\text{blue)} 
\end{smallmatrix}}{\mathop{F{{e}_{4}}[Fe{{(CN)}_{6}}]}}\,+12NaCl\)