Samarium

Symbol: Sm
Atomic number: 62
Category: lanthanides
Group: n/a
Period: 6
Block: f
Atomic weight: 150.36 g/mol
Electrons per shell: 2, 8, 18, 24, 8, 2
CAS number: 7440-12-2
Phase: solid
Density: 7.52 kg/dm³ (near room temperature)
Melting point: 1345 K (1072 °C, 1962 °F)
Boiling point: 2067 K (1794 °C, 3261 °F)
Crystal structure: rhombohedral
Oxidation states: 3
Electronegativity: 1.17 (Pauling scale)
Name's origin: samarskite
Name's meaning: a mineral found in the Urals and in North Carolina
Facts:
- is a rare earth metal, with a bright silver luster
- is reasonably stable in air; it ignites in air at 150 °C
- even with long-term storage under mineral oil, samarium is gradually oxidized, with a grayish-yellow powder of the oxide-hydroxide being formed
- the metallic appearance of a sample can be preserved by sealing it under an inert gas such as argon
- is used e.g. in carbon-air lighting, as a neutron absorber, for alloys, for headphone magnets
- is never found free in nature, but, like other rare earth elements, is contained in many minerals, including monazite, bastnäsite and samarskite
- is of low to moderate toxicity, although their toxicity has not been investigated in detail
- is composed of four stable isotopes, and three extremely long-lived radioisotopes