Chemical significance of ligand-field parameters in chromium(III) complexes of quadrate symmetry

Abstract

Electronic spectra of some complexes of the chromium(III) ion of general formula [CrX₄Z₂] have been interpreted using the crystal-field and angular-overlap models (X₄= a tetra-amine, two diamines, or four monoamines; Z= F, Cl, Br, I, dmf, or MeCO₂). Values of the various ligand-field parameters have been obtained and are discussed in terms of their chemical utility and their relation to ligand-field strength. A spectrochemical series in Cp, the second-order crystal-field parameter, has been derived and shown to reflect trends in the chromium-ligand interactions which are not apparent from the conventional spectrochemical series in Dq.