Which isotope of hydrogen is represented as "Deuterium"?

Deuterium is an isotope of hydrogen with a nucleus that contains one proton and one neutron, giving it a mass number of 2. This is specifically represented as Hydrogen-2 (²H). In contrast, Hydrogen-1 (¹H), also known as protium, has only one proton and no neutrons. Hydrogen-3 (³H), known as tritium, contains one proton and two neutrons, while Hydrogen-4 (⁴H) is not a stable isotope and does not commonly occur. Since deuterium has this unique combination of one proton and one neutron, it stands out as Hydrogen-2, differentiating it from other isotopes of hydrogen. Understanding these characteristics is essential in fields like nuclear chemistry and isotopic labeling in various scientific applications.