The periodic table/Samarium

Subject classification: this is a chemistry resource.

Educational level: this is a research resource.

Type classification: this is an article resource.

Completion status: this resource is considered to be complete.

Discovery

Paul-Émile Lecoq de Boisbaudran isolated a samarium salt in 1879 in Paris, France.
First, Boisbaudran extracted ‘didymium’ from the mineral samarskite and made a solution of ‘didymium’ nitrate. He then added ammonium hydroxide and found two precipitates were formed; one containing ‘didymium’ and the other a new element – samarium.
The new element samarium was named after the mineral samarskite in which it had been found.

Quick Facts

Name: Samarium

Symbol: Sm

Mass: 150.36

Classification: Lanthanides

Protons: 62

Electrons: 62

Neutrons: 88

Color: silvery-white

Discovered in: 1879

Electron Configuration: Xe 4f6 6s2

CAS Number: 7440-19-9

Appearance: silvery-white metal

Key Isotopes: 152Sm

Allotropes: α-samarium, β-samarium, γ-samarium

Density: 7.54 grams per cubic centimeter

Crystal Structure: rhombohedral

Melting Point: 1,074°C

Boiling Point: 1,794°C

Uses

Samarium is used as a catalyst for the dehydration and dehydrogenation of ethanol, and is also used in infrared absorbing glass.
Radioactive 153Samarium is used in the treatment of cancer.
Samarium is used as an absorb-er in nuclear reactors.
Main use of Samarium is in samarium-cobalt alloy magnets. These magnets are resistant to demagnetization.

Atomic Data

Atomic radius: 229 pm

Covalent radius: 198 pm

Electronegativity: 1.17

Electron affinity: 0.162 (theoretical)

Ionisation energies

First: 1st: 544.5 kJ/mol

Second: 2nd: 1070 kJ/mol

Third: 3rd: 2260 kJ/mol

Supply Risk

Relative supply risk: 9.5

Crustal abundance: 0.3 ppm

Recycling rate: <10%

Substitutability: High

Production concentration: 97%

Reserve distribution: 50%

Oxidation States and Isotopes

Common oxidation states: 3, 2

Isotopes

Isotope	Atomic mass	Abundance (%)
¹⁴⁴Sm	143.912	3.07
¹⁴⁷Sm	146.915	14.99
¹⁴⁸Sm	147.915	11.24
¹⁴⁹Sm	148.917	13.82
¹⁵⁰Sm	147.915	11.24
¹⁴⁸Sm	147.915	11.24
¹⁴⁸Sm	147.915	11.24

External Links

"Discovery of Samarium"

Search for Samarium on Wikipedia.