In chemistry, a hydron is the general name for a cationic form of atomic hydrogen, represented with the symbol . However, in most textbooks, this term is avoided and instead "proton" is used, which strictly speaking refers to the cation of protium, the most common isotope of hydrogen. The term "hydron" includes cations of hydrogen regardless of their isotopic composition: thus it refers collectively to protons (¹H⁺) for the protium isotope, deuterons (²H⁺ or D⁺) for the deuterium isotope, and tritons (³H⁺ or T⁺) for the tritium isotope. Unlike other ions, the hydron consists only of a bare atomic nucleus.