An Etymological Dictionary of Astronomy and Astrophysics

The first heavy → isotope of → hydrogen (²H), the → nucleus of which consists of one → proton and one → neutron. Like hydrogen, the deuterium atom has one electron, and therefore has similar chemical properties to hydrogen, forming, e.g., → heavy water (HDO). Deuterium is generated only during → Big Bang nucleosynthesis. It is destroyed in stars through the reaction D + p → ³He + γ (→ deuterium burning). As there is no net source of deuterium in stars, its abundance has decreased steadily since the → Big Bang, and any value measured today must be a lower limit on the primordial value. However, → fractionation processes lead to local → deuterium enhancements; see → deuterium abundance for more details. Theoretical models of Big Bang nucleosynthesis predict D/H to be (2.61 ± 0.15) x 10^-5 (Steigman et al. 2007, MNRAS 378, 576) and this is closely matched by measurements from
intergalactic Dα line absorption observations toward high-redshift quasars
that give 2.53±0.04 x 10^-5 (Cooke et al. 2014, ApJ 781, 31).
See also:

→ deuterated, → deuterated species, → deuterium enrichment, → deuterium enrichment factor, → deuterium fractionation, → deuteron.

See also: From Gk. deutero-, combining form of deuterios “second” + -ium suffix occurring in scientific coinages on a Latin model. Coined in 1933 by U.S. chemist Harold C. Urey (1893-1981).