Crystal field theory fails if one tries to explain the difference in spectra of two tris(aminoacidato)cobalt(III) complexes with practically identical coordination geometry. The application of the angular overlap model with the assumption of anisotropic Co-O interaction gives an explanation for the difference. © 1986.
Urland, W., & Niketić, S. R. (1986). Failure of crystal field theory: an example. Chemical Physics Letters, 129(6), 592–594. https://doi.org/10.1016/0009-2614(86)80406-7