EPR has been performed on single crystals of nominally pure ⁷Li₂O: (a) as grown, (b) after X-irradiation, and (c) after subsequent annealing: (a) shows evidence of several sites of Fe³⁺ in low abundance; (b) shows additional spectra from an electron centre with g=2.003(1), associated with a brown coloration of the crystal, and also from Fe³⁺ at tetragonal sites; (c) shows that the electron centre (and the coloration) has been destroyed and the tetragonal Fe³⁺ concentration has been greatly enhanced. The fine structure parameters of the tetragonal Fe³⁺ centres, b₂⁰=-0.1445(5) cm^-1, b₄⁰=-27(3)*10^-4 cm^-1 and b₄⁴=-90(2)*10^-4 cm^-1, are shown to be well described by the Newman superposition model, using a structural model for the centre comprising Fe³⁺ substituting for Li⁺ and two adjacent Li⁺ vacancies. Models are proposed for the changes that occur in this material on X-irradiation and annealing.