Heavy water

Heavy water

Names
IUPAC name (2H2)Water[4]
Other names Deuterium oxide[1] Water-d2[2] Dideuterium monoxide Deuterated water[3]
Identifiers
CAS Number	7789-20-0 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:41981 Y
ChEMBL	ChEMBL1232306 Y
ChemSpider	23004 Y
ECHA InfoCard	100.029.226
EC Number	232-148-9
Gmelin Reference	97
KEGG	D03703 Y
MeSH	Deuterium+Oxide
PubChem CID	24602
RTECS number	ZC0230000
UNII	J65BV539M3 Y
CompTox Dashboard (EPA)	DTXSID4051243
InChI InChI=1S/H2O/h1H2/i/hD2 N Key: XLYOFNOQVPJJNP-ZSJDYOACSA-N N
SMILES [2H]O[2H]
Properties
Chemical formula	D 2O
Molar mass	20.0276 g mol−1
Appearance	Colorless liquid
Odor	Odorless
Density	1.107 g mL−1
Melting point	3.82 °C; 38.88 °F; 276.97 K
Boiling point	101.4 °C (214.5 °F; 374.5 K)
Solubility in water	Miscible
log P	−1.38
Refractive index (nD)	1.328
Viscosity	1.25 mPa s (at 20 °C)
Dipole moment	1.87 D
Hazards
NFPA 704 (fire diamond)	1 0 0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N (what is YN ?) Infobox references

Heavy water (deuterium oxide, ²
H
₂O, D
₂O) is a form of water whose hydrogen atoms are all deuterium (²
H or D, also known as heavy hydrogen) rather than the common hydrogen-1 isotope (¹
H, also called protium) that makes up most of the hydrogen in normal water.^[3] 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 hydrogen isotope. Heavy water contains deuterium atoms and is used in nuclear reactors. Semiheavy water (HDO) is more common than pure heavy water, while heavy-oxygen water is denser but lacks unique properties. Tritiated water is radioactive due to tritium content.

Heavy water has different physical properties than regular water, such as being 10.6% denser and having a higher melting point. Heavy water is less dissociated at a given temperature, and it does not have the slightly blue color of regular water. While it has no significant taste difference, it can taste slightly sweet. Heavy water affects biological systems by altering enzymes, hydrogen bonds, and cell division in eukaryotes. It can be lethal to multicellular organisms at concentrations over 50%. However, some prokaryotes like bacteria 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.

Deuterated water (HDO) occurs naturally in normal water and can be separated through distillation, electrolysis, or chemical exchange processes. The most cost-effective process for producing heavy water is the Girdler sulfide process. Heavy water is used in various industries and is sold in different grades of purity. Some of its applications include nuclear magnetic resonance, infrared spectroscopy, neutron moderation, neutrino detection, metabolic rate testing, neutron capture therapy, and the production of radioactive materials such as plutonium and tritium.