In chemistry, a boranylium ion is an inorganic cation with the chemical formula BR+2, where R represents a non-specific substituent. Being electron-deficient, boranylium ions form adducts with Lewis bases. Boranylium ions have historical names that depend on the number of coordinated ligands: * [BR2]+: borinium * [BR2L]+: borenium * [BR2L2]+: boronium