Californium

Symbol: Cf
Atomic number: 98
Category: actinides
Group: n/a
Period: 7
Block: f
Atomic weight: (251) g/mol
Electrons per shell: 2, 8, 18, 32, 28, 8, 2
CAS number: 7440-71-3
Phase: solid
Density: 15.1 kg/l (near room temperature)
Melting point: 1173 K (900C, 1652F)
Boiling point: 1743 K (1470C, 2678F)
Crystal structure: hexagonal
Oxidation states: 2, 3, 4
Electronegativity: 1.3 (Pauling scale)
Name's origin: California
Name's meaning: a research group in University of California, Berkeley discovered the element and named it after the state
Facts:
- a radioactive transuranic element
- is used in starting nuclear reactors, optimizing coal-fired power plants and cement production facilities (via online analyzers), medical treatment of cancer, and oil exploration via down hole well loggin
- was first produced by bombarding curium with alpha particles (helium ions)
- twenty radioisotopes of californium have been characterized, the most stable being californium- 251 with a half-life of 898 years
- although californium does not occur naturally on Earth, the element and its decay products occur elsewhere in the universe
- has no biological role and only a few californium compounds have been made and studied
- is extremely radioactive and harmful