francium
Francium (Fr) is a radioactive alkali metal, resembling cesium, which has been obtained only in trace quantities. Its most stable isotope, 223Fr, has a half-life of 21 minutes.
| atomic number | 87 |
| relative atomic mass | 223.02 |
| relative density | 2.5 |
| melting point | 27°C (81°F) |
| boiling point | 677°C (1,251°F) |
