All practice pages/Interatomic theory/Elements

62Sm150.36

Element 62, a lanthanide

Samarium

The first element named, indirectly, after a person, and half of the magnets that keep working when things get hot.

At a glance

Symbol
Sm
Atomic number
62
Average atomic mass
150.36
Group
none; it sits in the lanthanide row below the table
Period
6
Family
lanthanide
Electron configuration
[Xe] 4f⁶ 6s²
Electronegativity
1.17
Common ions
Sm³⁺, and also Sm²⁺

On the table

Periodic table with Samarium highlighted123456789101112131415161718123456757-7189-103HHeLiBeBCNOFNeNaMgAlSiPSClArKCaScTiVCrMnFeCoNiCuZnGaGeAsSeBrKrRbSrYZrNbMoTcRuRhPdAgCdInSnSbTeIXeCsBaLaCePrNdPmSmEuGdTbDyHoErTmYbLuHfTaWReOsIrPtAuHgTlPbBiPoAtRnFrRaAcThPaUNpPuAmCmBkCfEsFmMdNoLrRfDbSgBhHsMtDsRgCnNhFlMcLvTsOg

Period 6, in the lanthanide row set below the main table. The other lanthanides are tinted, and every cell opens its own article.

Electrons and bonding

Like the other lanthanides, it gives up three electrons to form the Sm³⁺ ion in most of its compounds.

Properties

State at 25 °C
solid
What it looks like
silvery metal that tarnishes slowly in air
Melting point
1074 °C
Boiling point
1794 °C
Density
7.52 g/cm³

Where it is found

Found in monazite and bastnäsite, mostly mined in China.

Discovery and name

Paul-Émile Lecoq de Boisbaudran found it in 1879 in the mineral samarskite, which had been named after Vasili Samarsky-Bykhovets, a Russian mining engineer who supplied the samples. That makes samarium the first element named, by way of a mineral, after a person.

What it is used for

Samarium-cobalt magnets hold their strength at high temperatures and resist corrosion, so they are used in aerospace and military equipment and in some electric guitar pickups. Samarium-153 eases bone pain from cancer, samarium absorbs neutrons in reactor control rods, and samarium(II) iodide is a tool for organic chemists.

In compounds

SmCo₅samarium-cobalt magnetSm₂O₃samarium oxideSmI₂samarium(II) iodide