The deuterium atom has a mass about twice as great as an ordinary hydrogen atom. Heavy water is also called deuterium oxide.
Heavy water is useful in some kinds of nuclear reactors called heavy water reactors.
Because of the difference between the masses of the two kinds of hydrogen atoms, the physical properties of heavy water differ from those of ordinary water. Seeds will not germinate in it, and animals cannot live in it. Heavy water was first separated from ordinary water in 1932 by Gilbert N. Lewis, a chemist at the University of California. Peter A. Rock, Ph.D., Professor of Chemistry, Univ. of California, Davis. How to cite this article.