The periodic table/Samarium

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