or heavy hydrogen
hydrogen , chemical symbol 2 H or D, atomic number 1 (but atomic weight approximately 2).
Harold C. Urey won a Nobel Prize for its discovery and isolation. Its nucleus contains one proton and one neutron . A stable substance found in naturally occurring hydrogen compounds to the extent of about 0.015%, deuterium can be purified by distillation of hydrogen or by electrolysis of water . It enters into all the same chemical reactions as ordinary hydrogen; it forms D 2 and HD, analogous to molecular hydrogen (H 2 ), and D 2 O ( heavy water ), analogous to ordinary water (H 2 O). Nuclear fusion of deuterium atoms or of deuterium and {{link=tritium">tritium at high temperatures releases enormous amounts of energy . Such reactions have been used in nuclear weapon s and experimental power reactors. Deuterium is useful as a tracer in research into reaction mechanisms and biochemical pathways.