Electron resonance studies of transition metal oxyions, I. Experimental results for the manganate, hypomanganate and ferrate ions

Detailed electron spin resonance studies of single crystals of potassium chromate containing manganate and ferrate ions and of potassium orthovanadate containing hypom anganate ions are described and the appropriate spin Hamiltonians are determined. The results confirm the tetrahedral structure of these ions and the assignation of spin S = 1 to ferrate and hypomanganate. A discussion of the qualitative nature of the results shows that the unpaired electrons in these ions occupy a doubly degenerate molecular orbital.