Video: Complexation of iron(III) ion with chloride ion
Dissolving a hydrated iron(III) salt in nitric acid results in the formation
of the very pale purple (essentially colorless) hexaaquairon(III) ion, [Fe(OH2)6]3+(aq).
However, if hydrochloric acid is used, the yellow tetrachloroiron(III) ion,
[FeC14]-(aq), is formed.