Oxide chemistry. Part I. Ternary oxides containing nickel in oxidation states II, III, and IV

Abstract

Attempts to resolve differences in the literature concerning the structures and magnetic properties of the compounds BaNiO₂ and BaNiO₃ are reported. BaNiO₂ has the properties of an octahedral nickel(II) compound (SrNiO₂ cannot be obtained free from NiO). Nickel(III) systems, A₂NiO₄(A = La, Al, or Ga), have also been prepared. Equilibria in the BaNiO₂ BaNiO_2·5 BaNiO₃ system have been studied by thermogravimetric analysis: there is a continuous variation of composition with temperature, at least between the latter two members. LaNiO₃ and YNiO₃ are also described. Magnetic susceptibilities from 80 to 300 K are reported for all compounds.