deuterium (dōtērˈēəm) [key], isotope of hydrogen with mass no. 2. The deuterium nucleus, called a deuteron, contains one proton and one neutron. Deuterium is also called heavy hydrogen, and water in which the hydrogen atoms are deuterium is called heavy water (deuterium oxide, D2O). Deuterons are sometimes used in particle accelerators, and heavy water is used in "swimming pool" nuclear reactors as a moderator.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.
More on deuterium from Fact Monster:
See more Encyclopedia articles on: Compounds and Elements