On an intermediate electronic configuration of cobalt (+III)

Abstract

In a D 4h site with a strong elongation the 3A 2g term of cobalt (+III) can be stabilized with an electronic configuration intermediate between low spin ( 1A 1g) and high spin ( 5E g): d 2 xzd 2 yzd 1 xyd 1 z2d 0 x2 −y2. The La 2Li 0.5Co 0.5O 4 phase, whose layer structure favours strongly such a distortion of the CoO 6 octahedra, illustrates very well this possibility for cobalt (+III). 1A 1g → 3A 2g and 1A 1g → 5E g transitions appear as the temperature increases.