How Is Sodium Ferrocyanide Decahydrate Synthesized?

Sodium ferrocyanide decahydrate, Na4[Fe(CN)6]·10H2O, is synthesized by reacting ferrous sulfate heptahydrate (FeSO4·7H2O), sodium cyanide (NaCN), and calcium hydroxide [Ca(OH)2] in water. The reaction forms a precipitate of ferrous hydroxide [Fe(OH)2], which reacts with the cyanide ions to form ferrocyanide [Fe(CN)6]4-. Sodium ions then replace the calcium ions in the solution to form the final product, sodium ferrocyanide decahydrate. The resulting compound can be isolated by filtration, washed with water, and dried. It is important to handle sodium cyanide with extreme caution due to its toxic nature.