Introduction

Abstract

There have been various attempts to extend the diagrams of Tanabe and Sugano⁵⁹ to cover additional geometries of some interest, particularly those of tetragonally and trigonally distorted octahedra. In general, these treatments are not suitable for our purpose, since only a specific problem was covered or incomplete diagrams were produced. A notable exception is the work of Perumareddi⁴³ on the d ² and d ⁸ configurations. Unfortunately, the larger part of these diagrams is available only as a microfilm edition.