EPR Spectrum of the Oxygen Vacancy in Single Crystals V2O5

A new EPR spectrum of V2O5 is reported which is related to the non‐stoichiometry of the crystals. Its intensity increases on reduction and decreases on reoxidation. The spectrum is labelled El. El can be described by an S = 1 spin Hamiltonian with parameters gx = 1.33, gy = 2.51, gz = 1.01 (y ‖ b, x and z at angles of 25° to c and a), and D = 200 × 10−20 erg, E = −40 × 10−20 erg. E1 and the near‐infrared spectrum F1 (absorption bands at 1.25 and 1.52 eV with E ‖ a) are assigned to the two donor electrons from the oxygen vacancy in V2O5. The electrons are localized on nearest vanadium neighbours of the vacancy.