Deuteron mass
| Value | 3.3435837768e-27 kg |
| Status | Measured: ± 1.00e-36 kg (3.0e-10 relative) |
| Source | CODATA 2022 |
| Categories | Universal & AtomicNuclear |
| unified atomic mass unit (dalton) | 2.0135532 u |
| picogram | 3.3435838e-12 pg |
| nanogram | 3.3435838e-15 ng |
| microgram | 3.3435838e-18 μg |
| milligram | 3.3435838e-21 mg |
| centigram | 3.3435838e-22 cg |
| grain | 5.1599383e-23 gr |
| metric carat | 1.6717919e-23 ct |
| gram | 3.3435838e-24 g |
| pennyweight | 2.1499743e-24 dwt |
| dram | 1.8870632e-24 dr |
| ounce | 1.1794145e-25 oz |
| troy ounce | 1.0749871e-25 oz t |
| troy pound | 8.9582262e-27 lb t |
| pound | 7.3713404e-27 lb |
| kilogram | 3.3435838e-27 kg |
| stone | 5.2652432e-28 st |
| slug | 2.2910826e-28 slug |
| US hundredweight | 7.3713404e-29 cwt |
| UK long hundredweight | 6.5815540e-29 cwt (UK) |
| quintal | 3.3435838e-29 q |
| US short ton | 3.6856702e-30 ton |
| metric tonne | 3.3435838e-30 t |
| UK long ton | 3.2907770e-30 long ton |
| kilotonne | 3.3435838e-33 kt |
| megatonne | 3.3435838e-36 Mt |
| gigatonne | 3.3435838e-39 Gt |
| Earth mass | 5.5985797e-52 Mearth |
| solar mass | 1.6815364e-57 Msun |
Learning zone
Urey found deuterium in 1931 by distilling liquid hydrogen and looking for a shifted Balmer line. The deuteron is the simplest bound nucleus and the standard test of the nuclear force: it has just one bound state, no excited states, and a binding energy of only 2.224 MeV — one tenth the binding per nucleon of helium-4, and so weak that a single gamma ray above 2.224 MeV photodisintegrates it.
The mass shows the deficit directly: a proton plus a neutron is 1.007 276 + 1.008 665 = 2.015 941 u, while the deuteron is 2.013 553 u, short by 0.002 388 u = 2.224 MeV/c². Deuterium's practical uses trade on the extra neutron rather than the binding: D₂O moderates neutrons without absorbing them, deuterated solvents keep NMR spectra clean, and D-T fusion is the reaction every tokamak is built around.