Numerous synthetic routes have been used to prepare functional transition metal oxyfluorides to control the chemical composition with specific fluorination degree, particle size, morphology, and stabilization of desired crystal structures . In this work, we report on the two-step preparation of a new cobalt iron oxyfluoride with a rutile type structure, Co0.5Fe0.5O0.5F1.5, obtained by calcination of the hydrated fluoride CoFeF5(H2O)7. Subsequent electrocatalytic evaluations unveiled that Co0.5Fe0.5O0.5F1.5 is one of the highest performing cobalt-based OER catalysts reported to date, considering metrics of overpotential, Tafel slope, mass activity, and stability. Complementary lines of computational and mechanistic studies were carried out to elucidate that the existence of a bimolecular reaction mechanism that is deemed to be the origin of the high efficiency of Co0.5Fe0.5O0.5F1.5.