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

The pale-yellow LiMFeIO6 (M = K, Rb or Cs) have been prepared by reaction of MIO4, Li+ and [Fe(H2O)(6)](3+) in hot aqueous solution at pH 9. Olive-green LiMCoIO6 were prepared from MIO4, Li+ and [Co(H2O)(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'IO6 (M' = Mn, Ni, Ge, etc). Fe-57 Mossbauer data are reported for LiKFeIO6.