Isotopes of hydrogen

Hydrogen (1H) has three naturally occurring isotopes: 1H, 2H, and 3H. 1H and 2H are stable, while 3H has a half-life of 12.32 years. Heavier isotopes also exist; all are synthetic and have a half-life of less than 1 zeptosecond (10−21 s). Hydrogen is the only element whose isotopes have different names that remain in common use today: 2H is deuterium and 3H is tritium.

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