| Ferric ortho-antimonate, Fe2O3.Sb2O5 or FeSbO4, is obtained in the heptahydrated condition, 2FeSbO4.7H2O, by addition of excess of a concentrated solution of a ferric salt to a boiling solution of sodium antimonate. The di-antimonate, Fe2O3.2Sb2O5.11H2O, prepared by precipitating iron ammonium alum with potassium antimonate, is a yellow salt which becomes anhydrous at 100° C. |