Absorption Spectra of Heteropolyanions. II The Heteropolytungstates Containing Co(II), Co (III) or Mn(IV) as Central Ions

The visible and ultraviolet absorption spectra have been measured for some heteropolytungstates containing cobalt (II), cobalt (III) or manganese (IV) as central ions. It has been shown that some cobalt (II) or cobalt (III) ions in the heteropolytungstates have tetrahedral co-ordination. This is the first case of the absorption spectra of [CoII(O=)4]- and [CoIII(O=)4]-complexes being measured.