Heavy water

Heavy water (deuterium oxide, 2H2O, D2O) is a form of <a href="/facts/Water_(molecule)/FFsl65l1">water</a> in which hydrogen atoms are all <a href="/facts/Deuterium/Bv4wfCkw">deuterium</a> (2H or D, also known as heavy hydrogen) rather than the common hydrogen-1 <a href="/facts/Isotope/KD9B1y6o">isotope</a> (1H, also called protium) that makes up most of the hydrogen in normal water. The presence of the heavier isotope gives the water different nuclear properties, and the increase in mass gives it slightly different physical and chemical properties when compared to normal water.
Deuterium is a heavy <a href="/facts/Isotopes_of_hydrogen/c3CAg2Pc">hydrogen isotope</a>. Heavy water contains deuterium atoms and is used in <a href="/facts/Nuclear_reactor/8xqjIbge">nuclear reactors</a>. <a href="/facts/Semiheavy_water/SUexwQxx">Semiheavy water</a> (HDO) is more common than pure heavy water, while heavy-oxygen water is denser but lacks unique properties. Tritiated water is radioactive due to <a href="/facts/Tritium/HWSa6EHy">tritium</a> content.
Heavy water has different physical properties from regular water, such as being 10.6% denser and having a higher melting point. Heavy water is less <a href="/facts/Dissociation_(chemistry)/gDRGdeSN">dissociated</a> at a given temperature, and it does not have the slightly blue color of regular water. It can taste slightly sweeter than regular water, though not to a significant degree. Heavy water affects biological systems by altering enzymes, hydrogen bonds, and cell division in <a href="/facts/Eukaryote/SkwyPLMA">eukaryotes</a>. It can be lethal to multicellular organisms at concentrations over 50%. However, some <a href="/facts/Prokaryotes/oYyvaDDH">prokaryotes</a> like <a href="/facts/Bacteria/wC8xSCsU">bacteria</a> can survive in a heavy hydrogen environment. Heavy water can be toxic to humans, but a large amount would be needed for poisoning to occur.
The most cost-effective process for producing heavy water is the <a href="/facts/Girdler_sulfide_process/46uHuQQd">Girdler sulfide process</a>. Heavy water is used in various industries and is sold in different grades of purity. Some of its applications include <a href="/facts/Nuclear_magnetic_resonance/pGYAn9Bz">nuclear magnetic resonance</a>, <a href="/facts/Infrared_spectroscopy/u1Hzx617">infrared spectroscopy</a>, <a href="/facts/Neutron_moderation/1qa6YvDD">neutron moderation</a>, <a href="/facts/Neutrino_detection/LwtyrVAc">neutrino detection</a>, metabolic rate testing, <a href="/facts/Neutron_capture_therapy/FDbdUNkY">neutron capture therapy</a>, and the production of radioactive materials such as <a href="/facts/Plutonium/4bUw9zH3">plutonium</a> and tritium.

Heavy water open-in-new

Heavy water