An ESR study of the heterogeneous system Cr2O3V2O5

An ESR study of the ‘products’ of the high temperature solid state reaction xCr₂O₃+yV₂O₅ ($\text{0.05≦(}\text{x}\text{y}\text{)≦2.0}$), aided by powder X-ray diffraction and IR spectra, has revealed (i) ‘unfamiliar’ paramagnetic intermediates Cr⁴⁺ and Cr⁵⁺, (ii) provided some clues to the oxidation of Cr³⁺ to Cr⁶⁺, and (iii) demonstrated a variety of exchange interactions involving V⁴⁺ and Cr³⁺.