Deuterium is a colorless, odorless and non-toxic inflammable gas. Deuterium is a stable, naturally-occurring
isotope of hydrogen with an atomic mass of two (one proton and one neutron). Deuterium is sometimes called heavy hydrogen. When combined with oxygen, the oxide form is referred to as heavy water and is used to moderate fission reactions in certain nuclear reactors. Used in nuclear reactors, NMR spectroscopy, tracing, contrast properties, nuclear resonance spectroscopy and nuclear weapons.