Samarium (Sm)

Samarium properties

Atomic number

62

Atomic mass

150.36 u

Category

Lanthanide

Group

—

Period

6

Block

f-block

State at room temp.

Solid

Electronegativity

1.17

Melting point

1,345 K (1,071.8 °C)

Boiling point

2,067 K (1,793.8 °C)

Density

7.52 g/cm³

Valence electrons

2

Common charges

+2, +3

Oxidation states

+3, +2

Atomic radius

229 pm

Ionization energy

5.644 eV

Electron affinity

—

Radioactive

No, has stable isotopes

Discovered

1879

Samarium electron configuration

The electron configuration of Samarium (Sm) is [Xe] 4f6 6s2. Its 62 electrons are arranged in shells as 2, 8, 18, 24, 8, 2.

Protons, neutrons and electrons in Samarium

A neutral Samarium atom has 62 protons and 62 electrons. Most Samarium atoms have about 88 neutrons: the atomic mass rounded to 150, minus the atomic number 62.

Neutrons are approximate: atoms of the same element can have different numbers of neutrons (isotopes). Atomic number and mass

How many valence electrons does Samarium have?

2

Samarium has 2 valence electrons in its outermost shell. As an f-block element, its 4f or 5f electrons can also take part in bonding.

See every element: Periodic table with valence electrons

Samarium orbital diagram

Each box is an orbital that holds up to two electrons with opposite spins (↑↓). The inner shells are the same as the noble gas in brackets. How to write electron configurations

Molar mass of Samarium

150.36 g/mol

One mole of Samarium atoms (6.022 × 10²³ atoms) has a mass of 150.36 grams. Use this value to convert between grams and moles.

Samarium facts

• Samarium–cobalt magnets keep their strength at high temperatures, so they're used in motors and guitar pickups.
• Samarium (Sm) has atomic number 62 and is a solid at room temperature. It was discovered in 1879.

Position in the periodic table

Samarium is element 62, in period 6 of the periodic table. It is one of the Lanthanides in the f-block, shown in the rows below the main table.

All lanthanides

Uses of Samarium

Samarium-153 is used in medicine to relieve pain when cancer has spread to the bones. Samarium absorbs neutrons well, so it is used in some nuclear reactor control rods, and samarium oxide goes into special glass that absorbs infrared light. In chemistry labs, samarium(II) iodide is a useful reagent for building complex organic molecules.

Who discovered Samarium?

French chemist Paul-Émile Lecoq de Boisbaudran discovered samarium in Paris in 1879 by spectroscopy of an extract from the mineral samarskite. Samarskite was named after Russian mining official Vasili Samarsky-Bykhovets, making samarium the first element named, indirectly, after a person.

Where does the name come from?

Samarium is named after the mineral samarskite, in which it was found. The mineral honors Vasili Samarsky-Bykhovets, a Russian mining official, which makes samarium the first element named, indirectly, after a person.

Discovery timeline