Erbium (Er)

Erbium properties

Atomic number

68

Atomic mass

167.26 u

Category

Lanthanide

Group

—

Period

6

Block

f-block

State at room temp.

Solid

Electronegativity

1.24

Melting point

1,802 K (1,528.8 °C)

Boiling point

3,141 K (2,867.8 °C)

Density

9.066 g/cm³

Valence electrons

2

Common charges

+3

Oxidation states

+3

Atomic radius

235 pm

Ionization energy

6.108 eV

Electron affinity

—

Radioactive

No, has stable isotopes

Discovered

1843

Erbium electron configuration

The electron configuration of Erbium (Er) is [Xe] 4f12 6s2. Its 68 electrons are arranged in shells as 2, 8, 18, 30, 8, 2.

Protons, neutrons and electrons in Erbium

A neutral Erbium atom has 68 protons and 68 electrons. Most Erbium atoms have about 99 neutrons: the atomic mass rounded to 167, minus the atomic number 68.

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

How many valence electrons does Erbium have?

2

Erbium 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

Erbium 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 Erbium

167.26 g/mol

One mole of Erbium atoms (6.022 × 10²³ atoms) has a mass of 167.26 grams. Use this value to convert between grams and moles.

Erbium facts

• Erbium ions emit light near 1,550 nanometers, the wavelength at which glass optical fibers lose the least signal.
• Reasonably pure erbium metal was not produced until 1934, by reducing erbium chloride with potassium vapor.
• Erbium (Er) has atomic number 68 and is a solid at room temperature. It was discovered in 1843.

Position in the periodic table

Erbium is element 68, 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 Erbium

Erbium is essential to long-distance internet and phone connections: erbium-doped fiber amplifiers boost light signals in undersea and land cables without first converting them to electricity. Erbium lasers are used in dentistry and skin treatments because their light is strongly absorbed by water in tissue. Erbium oxide also gives glass, glazes, and cubic zirconia a pink color.

Who discovered Erbium?

Swedish chemist Carl Gustaf Mosander discovered erbium in 1843 in Stockholm while separating yttria, an oxide from the mineral gadolinite, into fractions. It is named after Ytterby, the Swedish village where gadolinite was found.

Where does the name come from?

Erbium is named after Ytterby, the Swedish village near Stockholm whose quarry yielded so many new elements. Carl Gustaf Mosander discovered erbium in 1843, taking its name from a piece of the village name.

Discovery timeline