Studies in eight-co-ordination. Part II. The electron spin resonance of, and crystal field in, calcium copper acetate hexahydrate

Abstract

The e.s.r. behaviour of single crystals of calcium copper acetate hexahydrate and calcium cadmium acetate hexahydrate containing ca. 0·5% copper has been investigated at Q-band frequencies in the temperature range from room temperature to that of liquid nitrogen. At room temperature g_∥= 2·365, g_⊥= 2·064, A_∥(⁶³Cu)= 0·0143, and A_⊥(⁶³Cu)= 0·0015 cm.^–1. At temperatures <140°K the e.s.r. measurements show that a small structural change occurs. The room-temperature e.s.r. data, coupled with published single-crystal polarised spectral measurements, are interpreted in terms of a simple crystal-field model. The nature of the bonding in the complex is also discussed.