IRON(III) PERCHLORATE HYDRATE

Chemical properties

yellow crystal(s); hygroscopic [STR93]

Preparation

This 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.

Purification Methods

Crystallise it twice from conc HClO4, the first time in the presence of a small amount of H2O2 to ensure that the iron is fully oxidised [Sullivan J Am Chem Soc 84 4256 1962]. Extreme care should be taken with this preparation because it is potentially EXPLOSIVE.