Deuterium
Definition and meaning of Deuterium in chemistry.
Deuterium is a naturally occurring, stable isotope of hydrogen whose nucleus contains one proton and one neutron, giving it about twice the mass of ordinary hydrogen (protium).
In more detail
Deuterium is symbolized D or ²H and makes up roughly 0.0156% of natural hydrogen atoms, occurring mainly as HD or in trace amounts of D2O within ordinary water. Because carbon-deuterium and oxygen-deuterium bonds are slightly stronger and vibrate more slowly than bonds to protium, deuterium-labeled reactions typically proceed more slowly, a phenomenon called the kinetic isotope effect. This mass difference makes deuterium useful as a nonradioactive tracer for following reaction mechanisms and metabolic pathways, and deuterated solvents (like CDCl3) are standard in proton NMR spectroscopy since they lack interfering ¹H signals. Deuterium oxide, or heavy water, also serves as a neutron moderator in some nuclear reactor designs.
Key facts
| Symbol | D or ²H |
|---|---|
| Mass number | 2 (1 proton + 1 neutron) |
| Natural abundance | ~0.0156% of hydrogen atoms |
| Field | General Chemistry |
Heavy water (D2O) is used as a neutron moderator in CANDU nuclear reactors because deuterium slows fast neutrons effectively while absorbing far fewer of them than ordinary hydrogen does.
Frequently asked questions
Is deuterium radioactive?
No. Deuterium is a stable, non-radioactive isotope, unlike tritium (³H), which decays by beta emission.
What is 'heavy water'?
Heavy water is water in which the hydrogen atoms are deuterium instead of protium, giving the compound D2O rather than H2O.