Sodium ferrocyanide, Na₄Fe(CN)₆

Sodium ferrocyanide, Na₄Fe(CN)₆.10H₂O, may be prepared in an analogous manner to the potassium salt. It may also be prepared by boiling Prussian blue with aqueous solutions of sodium carbonate or hydroxide.

Its solubility in water is as follows: -

Temperature, °C.	20	30	42	60	80	98.5
Grams Na4Fe(CN)6 per 100 grams H2O	17.9	23.5	30.2	42.5	59.2	63.0

At 25° C., 20.725 grams of Na₄Fe(CN)₆ dissolve in 100 grams of water, the density of the solution being 1.0595. It yields beautiful monoclinic crystals, pale yellow in colour. Alcohol precipitates the nonahydrate, Na₄Fe(CN)₆.9H₂O, from the aqueous solution of the salt.