Evaluation of the Racah B parameters

2 Evaluation of Racah B parameters Two electronic configurations that are particularly conducive to the evaluation of B are 3d3 and 3d5, exemplified by Cr3+ and Fe3+ or Mn2+, respectively. For Cr3+ in an octahedral site the Racah B parameter is calculated from 

Racah B parameters have also been calculated for Mn2+ and Fe3+ in several minerals (Manning, 1970 Keester and White, 1968). In these 3d5 cations, two 

Values of B derived from crystal field spectra of Mn2+- and Fe3+-bearing minerals, which are listed in tables 5.14 and 5.15, are plotted in fig. 11.1. As for trivalent Cr, the formal charges on divalent Mn and trivalent Fe in oxide and silicate minerals are much lower than the field-free cation values as a result of covalent bonding in the crystal structures. 

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