Semiheavy water

Semiheavy water
Names
IUPAC name
(2H1)Water
Other names
Deuterium hydrogen monoxide
Deuterium hydrogen oxide, Water-d1, Water-d
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
115
  • InChI=1S/H2O/h1H2/i/hD
    Key: XLYOFNOQVPJJNP-DYCDLGHISA-N
  • [2H]O
Properties
H2HO or HDO
Molar mass 19.0214 g mol−1
Appearance Very pale blue, transparent liquid, very similar to regular water
Density 1.054 g cm−3
Melting point 3.81 °C (38.86 °F; 276.96 K)
Boiling point 100.74 °C (213.33 °F; 373.89 K)
miscible
log P −0.65
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Semiheavy water is the result of replacing one of the protium (normal hydrogen, 1H) in normal water with deuterium (2H; or D). It exists whenever there is water with 1H and 2H in the mix. This is because hydrogen atoms (1,2H) are rapidly exchanged between water molecules. Water with 50% 1H and 50% 2H, is about 50% H2HO and 25% each of H2O and 2H2O, in dynamic equilibrium. In normal water, about 1 molecule in 3,200 is HDO (1H2HO) (one hydrogen in 6,400 is 2H). By comparison, heavy water D2O or 2H2O occurs at a proportion of about 1 molecule in 41 million (i.e., 1 in 6,4002). This makes semiheavy water far more common than "normal" heavy water.

The freezing point of semiheavy water is close to the freezing point of heavy water at 3.81°C compared to the 3.82°C of heavy water.