Synthesis and properties of alkali-metal lithium periodatoferrate(III) and periodatocobaltate(III) complexes

Abstract

The pale-yellow LiMFeIO ₆ (M=K, Rb or Cs) have been prepared by reaction of MIO ₄ , Li ⁺ and [Fe(H ₂ O) ₆ ] ³⁺ in hot aqueous solution at pH 9. Olive-green LiMCoIO ₆ were prepared from MIO ₄ , Li ⁺ and [Co(H ₂ O) ₆ ] ²⁺ in hot alkaline solution using ozonised oxygen as oxidant. These insoluble powders have been characterised by analysis, IR and Raman, UV–VIS and EPR spectroscopy and magnetic measurements. PXRD studies revealed that they are amorphous, but structural data have been obtained via Fe or Co and I K-edge EXAFS, and are consistent with a layered periodate structure type similar to that found previously in MM′IO ₆ (M′=Mn, Ni, Ge, etc). ⁵⁷ Fe Mössbauer data are reported for LiKFeIO ₆ .