Cf
Californium
Element 98 · 251.07959 u
Californium is a powerful neutron source used in nuclear reactor startup and cancer treatment.
Physical Properties
| Atomic Mass | 251.07959 u |
| Density | 15.1 g/cm³ |
| Melting Point | 1173.0 K |
| Boiling Point | 1743.0 K |
| Appearance | Silvery metallic |
| State at Room Temp | Solid |
Chemical Properties
| Electronegativity | 1.3 (Pauling) |
| 1st Ionization Energy | 608.0 kJ/mol |
| Electron Affinity | -97.31 kJ/mol |
| Oxidation States | +2, +3, +4 |
Atomic Properties
| Electron Configuration | [Rn] 5f10 7s2 |
| Atomic Radius | 169.0 pm |
| Van der Waals Radius | 245.0 pm |
Discovery
| Discovered By | Stanley G. Thompson, Kenneth Street Jr., Albert Ghiorso, Glenn T. Seaborg |
| Discovery Year | 1950 |
| Location | Berkeley, California, USA |
| Named After | Named after California and the University of California |
About Californium
Californium-252 spontaneously fissions, emitting useful neutrons. Only about 500 micrograms are produced annually in the US. It is one of the most expensive substances on Earth.
Uses & Applications
Nuclear reactor startup, moisture gauges, oil well logging, and cancer treatment.
Fun Fact
Californium-252 costs around $27 million per gram, though only microgram quantities are typically needed.
Isotopes
| Mass Number | Abundance | Half-Life | Stable |
| 249 | - | 351 years | No |
| 251 | - | 898 years | No |
| 252 | - | 2.645 years | No |
Electron Configuration
[Rn] 5f10 7s2