Perchloric acid, iron(3+) salt (3:1)

PreparationThis crystallizes as the pale pink decahydrate Fe(ClO4)3.10H2O from solutions of iron(III) chloride or hydrous iron(III) oxide in perchloric acid. Upon standing over phosphorus pentoxide the decahydrate becomes the hexahydrate ; a 9-hydrate crystallizes from solution above 42°. This salt has been important in the study of the hydrated Fe3+ ion since perchlorate ions have only very low coordinating ability.