Californium is a man-made radioactive actinide with atomic symbol Cf, atomic number 98, and atomic weight 251.The pure metal is silvery-white, malleable and so soft it can be easily sliced with a razor blade.
Californium was first synthesized at the University of California at Berkeley. It was created in 1950 by bombarding curium with alpha particles. Californium is generated in nuclear reactors and particle accelerators. It’s the second heaviest element to be produced in a large enough amount to be seen by the naked eye.
Atomic number 98
Atomic mass 251
Melting point 900°C, 1652°F, 1173 K
Boiling point 1470 °C, 2678°F 1743 K
Group Actinides; Period 7; Block f
There are twenty radioisotopes of californium, with mass numbers from 237 to 256. The most stable is californium-251, with a half-life of 898 years, but the first to be discovered was californium-245, which has a half-life of only 44 minutes. Californium-252 is a very strong neutron emitter. One microgram releases 170 million neutrons per minute, which presents biological hazards. Proper safeguards should be used in handling californium.
Californium is used in portable metal detectors, for identifying gold and silver ores, to identify water and oil layers in oil wells and to detect metal fatigue and stress in aeroplanes. Californium-252 is also used to analyze the sulfur content of petroleum and can be used to inspect airline baggage.
Californium is known to be one of the most expensive materials on the earth due to its cost of transportation, limited availability, and expensive production process.
