Crystal field stabilization and tendency towards complex formation of first transition group elements

Abstract

AbstractThe increased affinity towards complex formation exhibited by metal ions with an unfilled d‐shell is related to the crystal field stabilization of such compounds and furnishes an explanation of what is the basis of the so‐called Irving‐Williams rule. The orbital degeneracy of the ground term determines the symmetry of the configuration and is thus responsible for irregularities in the complexity constants.If the total spin quantum number changes during a set of consecutive complex formation steps, a sudden change of activation energies and formation constants is to be expected, as recently has been verified. The activation energies are then expected and found high only when the crystal field stabilization is large and the orbital degeneracy one. High reaction rates on the other hand are to be expected for complete or half‐complete d‐shells without crystal field stabilization, and for nearly complete d‐shells if the orbital degeneracy is higher than one.