Magnetic Investigations of Spin-free Cobaltous Complexes. V. Tetra-azido and Tetracyanato Cobaltate(II) Ions

Abstract

The electronic spectra between 0.4 and 2.0 - and the magnetic susceptibilities between 70 and 300 ts K of the tetraazidoand tetraiso-cyanatocobaltate (II) ions, STACo(N/sub 3/)/sub 4/!/sup 2-/ and STACo(NCo)/sub 4/!/sup 2-/, are reported. These results are interpreted using ligand field theory to show the following structural and electronic features of these complex ions: (1) they are tetrahedral; (2) in STACo(NCo)/sub 4/ !/sup 2-/ it is almost certainly the nitrogen atoms that are bound to the Co(II); (3) -- NCo/sup -/ lies toward the stronger end in the spectrochemical series but toward the weaker end in the nephelauxetic series relative to N/sup -//sub 3/ (4) the metal-ligand bonds possess covalent character; and (5) the spin-orbit coupling constants of Co(II) in these complexes are 65 to 85% of the free-ion value. (auth)