| Quantity | Value | Units | Value | Units |
| Atomic number | 2 | |||
| Atomic mass | 4.002602(2) | g mole-1 | ||
| Density | 0.125 | g cm-3 | ||
| Mean excitation energy | 41.8 | eV | ||
| Minimum ionization | 1.936 | MeV g-1cm2 | 0.2418 | MeV cm-1 |
| Nuclear collision length | 51.8 | g cm-2 | 415.1 | cm |
| Nuclear interaction length | 71.0 | g cm-2 | 568.4 | cm |
| Pion collision length | 79.5 | g cm-2 | 636.2 | cm |
| Pion interaction length | 103.6 | g cm-2 | 829.5 | cm |
| Radiation length | 94.32 | g cm-2 | 755.2 | cm |
| Critical energy | 208.25 | MeV (for e-) | 203.34 | MeV (for e+) |
| Molière radius | 9.60 | g cm-2 | 76.90 | cm |
| Plasma energy |
7.20 | eV | ||
| Muon critical energy | 2020. | GeV | ||
| Boiling point @ 1 atm | 4.220 | K | -268.9 | C |
| Index of refraction (@ STP, Na D) | 1.02 |