Samarium
Definition and meaning of Samarium in chemistry.
Samarium is a chemical element with the symbol Sm and atomic number 62. It is a moderately hard, silvery metal belonging to the lanthanide series of rare-earth elements. Samarium slowly oxidizes in atmospheric air at room temperature and spontaneously ignites when heated to 150 degrees Celsius.
In more detail
Positioned in the f-block of the periodic table, samarium typically exhibits a highly stable +3 oxidation state in its chemical compounds, which are very often pale yellow in appearance. Unusually for a lanthanide, it can also readily form stable chemical compounds in the +2 oxidation state, such as samarium(II) iodide, which serves as a widely used reducing agent in synthetic organic chemistry. Samarium is found natively in several complex minerals, primarily monazite and bastnasite, from which it is commercially extracted using advanced solvent extraction techniques. It has absolutely no known biological role within living organisms but displays relatively low chemical toxicity. The elemental metal is quite notable for its strong neutron-absorbing properties, making specific isotopes incredibly valuable for constructing nuclear reactor control rods. Its magnetic properties, while somewhat weaker than neodymium, allow for the creation of permanent magnets possessing extremely high temperature stability.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Sm |
| Atomic number | 62 |
| Atomic mass | 150.36 u |
| Category | Lanthanide |
| State at room temperature | Solid |
| Melting point | 1072 °C |
| Year discovered | 1879 |
Samarium-cobalt magnets are utilized heavily in precision military and aerospace applications where highly reliable magnetic performance at elevated temperatures is strictly required by structural engineers.
Frequently asked questions
What exactly is samarium(II) iodide used for?
Also known formally as Kagan's reagent, samarium(II) iodide is a highly popular single-electron reducing agent used to facilitate carbon-carbon bond formation in complex organic chemistry.
Is pure samarium metal magnetic on its own?
Samarium itself is merely paramagnetic at room temperature, but it successfully forms highly coercive permanent magnets when it is properly alloyed with transition metals like cobalt.