Deuterated compounds

A deuterium label in heavy water is indicated by writing [2H₂]water or water-d₂, and similarly for other labelled compounds.  Compounds in which H atoms have been replaced by D are used for a variety of purposes, e.g. as solvents in 1H NMR spectroscopy. In a fully deuterated material, the D-for-H exchange can have significant effects on the properties of the compound as is shown in Table 9.2 for H₂O and D₂O. The difference in boiling points indicates that intermolecular hydrogen bonding (see Sections 6.2 and 9.6) is stronger in D₂O than in H₂O. The major industrial use of D₂O is as a moderator in nuclear reactors; D has a much lower cross-section for neutron capture than H, and D₂O is a suitable material for reducing the energies of fast neutrons produced in fission without appreciably diminishing the neutron flux.

Table 9.2 Selected properties of H₂O and D₂O (‘heavy water’).

Many fully or partially deuterated compounds are available commercially, and the extent of deuterium labelling  can be determined by mass spectrometry, density measurements (after conversion into water) or IR spectroscopy.