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Deuterium occurs in trace amounts naturally as deuterium gas (2 H 2 or D 2), but most deuterium atoms in the Universe are bonded with 1 H to form a gas called hydrogen deuteride (HD or 1 H 2 H). [12] Similarly, natural water contains deuterated molecules, almost all as semiheavy water HDO with only one deuterium.
Deuterium, 2 H (atomic mass 2.014 101 777 844 (15) Da), the other stable hydrogen isotope, has one proton and one neutron in its nucleus, called a deuteron. 2 H comprises 26–184 ppm (by population, not mass) of hydrogen on Earth; the lower number tends to be found in hydrogen gas and higher enrichment (150 ppm) is typical of seawater .
Heavy water (deuterium oxide, 2 H 2 O, D 2 O) is a form of water in which 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]
Deuterium-depleted water has less deuterium (2 H) than occurs in nature at sea level. [1] Deuterium is a naturally-occurring, stable (non-radioactive) isotope of hydrogen with a nucleus consisting of one proton and one neutron. A nucleus of normal hydrogen (protium, 1 H) consists of one proton only, and no
Hydrogen deuteride is an isotopologue of dihydrogen composed of two isotopes of hydrogen: the majority isotope 1 H and 2 H . Its proper molecular formula is 1 H 2 H, but for simplification, it is usually written as HD.
Semiheavy water is the result of replacing one of the protium (normal hydrogen, 1 H) in normal water with deuterium (2 H; or less correctly, [1] D). [2] It exists whenever there is water with 1 H and 2 H in the mix. This is because hydrogen atoms (1,2 H) are rapidly exchanged between water molecules.
Due to confusion over multiple water standards, the Commission on Isotopic Abundances and Atomic Weights recommended in 1994 that all future isotopic measurements of oxygen-18 (18 O) and deuterium (2 H) be reported relative to VSMOW, on a scale such that the δ 18 O of SLAP is −55.5‰ and the δ 2 H of SLAP is −428‰, relative to VSMOW.
Normal hydrogen (protium, 1 H) has no neutron. Deuterium (2 H) has one neutron, and tritium (3 H) has two. Neutrons add mass to the atom, leading to different chemical physical properties. This effect is especially strong for hydrogen isotopes, since the added neutron doubles the mass from 1 H to 2 H.