Periodic Table of Elements




Heavy Water D2O

Heavy water, also called as deuterium oxide or 2H2O or D2O, is a form of water that contains a larger than normal amount of the hydrogen isotope deuterium, which is also known as "heavy hydrogen".

Physical and chemical properties

  • Heavy water was discovered by Urey in 1932.
  • One part of heavy water is present in 6000 parts of ordinary water.
  • Physical State: liquid
  • Appearance: Very pale blue, transparent liquid
  • Odor: Odorless
  • Molecular Formula: 2H2O or D2O
  • Molar mass: 20.0276 g/mol
  • Density: 1.11 g/cm
  • Boiling point: 213.8F (101C)
  • Melting point: 38.84F (3.8C)
  • Vapor Pressure: 16.4 mm Hg
  • Specific heat of fusion: 0.3096 kj/g
  • Refractive index: 1.328
  • Viscosity: 0.001095 Pa s at 25C
  • Chemical reactions of heavy water are slower than that of ordinary water.
  • Reaction with metals:
    Heavy water reacts with alkali metals and alkaline earth metals to form heavy hydrogen (D2).
    D2O + 2Na 2NaOD + D2
  • Reaction with metal oxides:
    Heavy water reacts slowly with metal oxides to form corresponding deuteroxides.
    Na2O + D2O 2NaOD
  • Reaction with non-metal oxides:
    Heavy water reacts with non-metal oxides to form corresponding deutero acid.
    SO3 + D2O D2SO4
  • Reaction with metal carbides:
    Heavy water reacts with metal carbides to form corresponding deutero carbons or heavy hydrocarbons.
    CaC3 + 2D2O Ca(OD)2 + C2D2

Preparation of heavy water

It can be prepared by exhaustive electrolysis of ordinary water contaning little alkali NaOH or fractional distillation of ordinary water. One litre of heavy water is produced by the electrolysis of 30 litres of ordinary water.

Uses of heavy water

  • Heavy water is used as moderator in nuclear reactors.
  • It is used as tracer in study of mechanism of physiological process.
  • It is used in preparation of deuterium compounds.