deutérium

Deutérium, also known as deuterium, is a stable isotope of hydrogen with one proton and one neutron in its nucleus. Its nucleus, a deuteron, has a mass close to 2 atomic mass units. Chemically, deuterium behaves similarly to ordinary hydrogen, but its greater mass leads to noticeable differences in reaction rates and physical properties.

Natural abundance of deuterium is about 0.015% of hydrogen on Earth. The D/H ratio in standard mean ocean water is approximately 1.56 × 10^-4, making deuterium the most common stable isotope of hydrogen. Deuterium is produced in trace amounts during stellar and planetary processes and is primarily found in water as part of heavy water (D2O) and in organic molecules after hydrogen exchange.

Production and separation technologies focus on enriching deuterium from natural water or hydrogen. Methods include electrolysis, fractional distillation of water, and isotope exchange processes such as the Girdler sulfide process. Large-scale production for industrial use often relies on these techniques to obtain heavy water for specific applications.

Applications of deuterium are diverse. Heavy water is used as a neutron moderator in certain types of nuclear reactors, notably heavy-water reactors. In fusion research, deuterium serves as a fuel component in deuterium–tritium reactions. Deuterium and deuterated compounds are widely used as tracers in chemistry and biology, and deuterated solvents are valuable in nuclear magnetic resonance spectroscopy and in isotopic labeling of molecules.

History and naming: deuterium was identified by Harold Urey and others in 1931, with the element named for the Greek word deuter, meaning "second," reflecting its status as the second hydrogen isotope. Urey received the Nobel Prize in Chemistry in 1934 for the discovery.