|
|
| General |
| Name, Symbol, Number |
francium, Fr, 87 |
| Chemical series |
alkali metals |
| Group, Period, Block |
1, 7, s |
| Appearance |
metallic |
| Standard atomic weight |
(223) g·mol−1 |
| Electron configuration |
[Rn] 7s1 |
| Electrons per shell |
2, 8, 18, 32, 18, 8, 1 |
| Physical properties |
| Phase |
? solid |
| Density (near r.t.) |
1.87 g·cm−3 |
| Melting point |
? 300 K
(27 °C, 80 °F) |
| Boiling point |
? 950 K
(? 677 °C, ? 1250 °F) |
| Heat of fusion |
ca. 2 kJ·mol−1 |
| Heat of vaporization |
ca. 65 kJ·mol−1 |
Vapor pressure (extrapolated)
| P(Pa) |
1 |
10 |
100 |
1 k |
10 k |
100 k |
| at T(K) |
404 |
454 |
519 |
608 |
738 |
946 |
|
| Atomic properties |
| Crystal structure |
? cubic body centered |
| Oxidation states |
1
(strongly basic oxide) |
| Electronegativity |
0.7 (Pauling scale) |
| Ionization energies |
1st: 380 kJ/mol |
| Miscellaneous |
| Magnetic ordering |
? |
| Electrical resistivity |
? 3 µΩ·m |
| Thermal conductivity |
(300 K) ? 15 W·m−1·K−1 |
| CAS registry number |
7440-73-5 |
| Selected isotopes |
Main article: Isotopes of infobox francium
| iso |
NA |
half-life |
DM |
DE (MeV) |
DP |
| 221Fr |
syn |
4.8 min |
α |
6.457 |
217At |
| 222Fr |
syn |
14.2 min |
β– |
2.033 |
222Ra |
| 223Fr |
syn |
22.00 min |
β– |
1.149 |
223Ra |
| α |
5.430 |
219At |
|
| References |
