Properties
More associated than H
2O. mp 3.81°; triple point
temp 3.82°. bp 101.42°. Critical temp 371.5°. d
25 1.1044. Temp of max density 11.23°; d
11.23 1.1059. Sp heat of liquid (4-25°) 1.028 cal/g/°C. Heat of fusion 1.501
kcal/mole: Long, Kemp,
J. Am. Chem. Soc. 58, 1829 (1936). Heat of evapn 9.917 kcal/mole. Dielectric
const (25°): 78.06, Vidulich
et al., J. Phys. Chem. 71, 656 (1966). Dipole moment
in benzene (25°) 1.78, in dioxane 1.87. The surface tension is very
slightly smaller and the viscosity at 25° is 1.23 times as great as
that of water. On mixing with water, heat is evolved. Reacts with
hydrogen at 100° in the presence of 0.2 to 1
N NaOH forming
DOH + HD + OD
-. Ionization const 1.95 × 10
-15: W. F. K. Wynne-Jones,
Trans. Faraday Soc. 32, 1397 (1936). pK (25°) 14.955 (molarity scale); 16.653 (mole fraction scale): A. K. Covington
et al., J. Phys. Chem. 70, 3820 (1966).
See also Water.
To study chemical reaction rates and mechanisms.
The cross section of deuterium for the capture of thermal neutrons
is very low which makes it useful, in the form of heavy water, as
a neutron moderator in nuclear reactors. Produces a considerable
decrease in neutron energy per collision.