57Fe Mossbauer spectroscopy has been used to investigate the mechanisms of oxidation in Ni(II)–Fe(II) hydroxides and its role in the synthesis of pyroaurite-type NiFe-LDH,the oxidation state of iron in complexes such as [Fe(CN)6]3_/4_ intercalated in LDHs and ferrocene sulfonates intercalated in LDHs.