Deuterium
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Template:Stable Isotope Deuterium, also called heavy hydrogen, is a stable isotope of hydrogen with a natural abundance of one atom in 6500 of hydrogen. The nucleus of deuterium, called a deuteron, contains one proton and one neutron, whereas a normal hydrogen nucleus just has one proton.
The chemical symbol 2H identifies deuterium. The unofficial symbol D is also often used, even though deuterium is not a chemical element in its own right. It occurs naturally as deuterium gas, written 2H2 or D2. When bonded with a typical 1H atom, the gas is called hydrogen deuteride.
Deuterium behaves chemically identically to ordinary hydrogen, although, because of the greater atomic mass, reactions involving deuterium tend to occur at a somewhat slower reaction rate than the corresponding reactions involving ordinary hydrogen. The two isotopes can be distinguished physically by using mass spectroscopy.
Deuterium can replace the normal hydrogen in water molecules to form heavy water (D2O). Although not strictly toxic, consumption of heavy water could nevertheless pose a health threat.
The existence of deuterium in stars is an important datum in cosmology. Stellar fusion destroys deuterium, and there are no known natural processes, other than the Big Bang nucleosynthesis, which produce deuterium. Thus it is one of the arguments in favour of the Big Bang theory over the steady state theory of the universe.
The world's leading producer of deuterium is Canada, in the form of heavy water as neutron moderator for the operation of the CANDU reactor.
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Applications
Deuterium is useful in nuclear fusion reactions, especially in combination with tritium, because of the large reaction rate (or cross section) and high energy yield of the D-T reaction.
In chemistry and biochemistry, deuterium is used in tracer molecules to study chemical reactions and metabolic pathways because chemically it behaves identically to ordinary hydrogen, but it can be distinguished from ordinary hydrogen by its mass using mass spectrometry.
History
Deuterium was first detected in 1931 by Harold Clayton Urey, a chemist at Columbia University. Urey earned the 1934 Nobel Prize in Chemistry for this work. Gilbert Newton Lewis isolated the first sample of pure heavy water in 1933.
During World War II, Germany was known to be conducting experiments using heavy water as moderator for a nuclear reactor. This was a source of concern because it might allow them to produce plutonium for an atomic bomb. Ultimately it led to an important Allied operation, the Norwegian heavy water sabotage, to destroy the Vemork deuterium production facility in Norway.
Data
- density: 0.180 kg/m3 at STP (0 °C, 101.325 kPa).
- atomic weight: 2.01363.
Data at approximately 18 K for D2 (triple point):
- density:
- solid: 195 kg/m3
- gas: 0.452 kg/m3
- viscosity: 1.3 µPa·s
- specific heat capacity at constant pressure cp:
- solid: 2950 J/(kg·K)
- gas: 5200 J/(kg·K)
Anti-deuterium
An antideuteron is the antipatrticle of the nucleus of deuterium, consisting of an antiproton and an antineutron. The antideuteron was first produced at CERN and the Brookhaven National Laboratory in 1965. A complete atom, with a positron orbiting the nucleus, would be called antideuterium, but as of 2005 antideuterium has not yet been created.
References
- Nuclear Data Evaluation Lab (http://atom.kaeri.re.kr/)
- Desktop nuclear fusion demonstrated with deuterium gas (http://www.newscientist.com/article.ns?id=dn7315) (New Scientist)
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