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Ligand Field Theory & Spectra

  1. Derek W. Smith

Published Online: 15 MAR 2006

DOI: 10.1002/0470862106.ia120

Encyclopedia of Inorganic Chemistry

Encyclopedia of Inorganic Chemistry

How to Cite

Smith, D. W. 2006. Ligand Field Theory & Spectra. Encyclopedia of Inorganic Chemistry. .

Author Information

  1. University of Waikato, Hamilton, New Zealand

Publication History

  1. Published Online: 15 MAR 2006

Abstract

In any chemical environment – traditionally represented as a crystal field (CF), in which the donor atoms are represented by point charges – an nd subshell loses its fivefold degeneracy. The consequent splitting is described in detail for cubic (octahedral and tetrahedral) systems. The pure CF approach has serious shortcomings, but the effects of covalency can be accommodated without losing its simplicity altogether; this is often called ligand field theory (LFT). CF/LFT is important in the interpretation of the d–d spectra of complexes; the d–d states arising from cubic dn systems and their relative energies are analyzed, along with a discussion of the nephelauxetic effect. As examples of the analysis of d-orbital splittings in noncubic complexes, chlorocuprates(II) and tetragonal tetraamminechromium(III) complexes are examined in detail, using the angular overlap and cellular ligand field models. Among applications of LFT, ligand field stabilization energy (LFSE) is useful in the rationalization of thermodynamic and kinetic observations. The Jahn–Teller effect is important in the structural chemistry of copper(II) especially.

Keywords:

  • atomic orbital;
  • crystal field;
  • ligand field;
  • angular overlap model;
  • d-d spectra;
  • selection rules;
  • cellular ligand field model;
  • crystal field stabilization energy;
  • Jahn–Teller effect