Element Erbium Facts

The element erbium or Er is a silvery-white, malleable rare earth metal belonging to the lanthanide group. While you may not recognize this element on sight, you can credit the pink color of glass and man-made gems to its ion. Here are more interesting erbium facts:

Erbium Basic Facts

Atomic Number: 68

Symbol: Er

Atomic Weight: 167.26

Discovery: Carl Mosander 1842 or 1843 (Sweden)

Electron Configuration: [Xe] 4f¹² 6s²

Word Origin: Ytterby, a town in Sweden (also the source of the name of the elements yttrium, terbium, and ytterbium)

Interesting Erbium Facts

• Erbium was one of three elements found in "yttria" that Mosander separated from the mineral gadolinite. The three components were called yttria, erbia, and terbia. The components had similar names and properties, which became confusing. Mosander's erbia later became known as terbia, while the original terbia became erbia.
• Although erbium (along with several rare earths) was discovered in the mid-19th century, it was not isolated as a pure element until 1935 because the group of elements had such similar properties. W. Klemm and H. Bommer purified erbium by reducing anhydrous erbium chloride with potassium vapor.
• Although a rare earth, erbium is not all that rare. The element is the 45th most abundant in the Earth's crust, at a level of about 2.8 mg/kg. It is found in seawater at concentrations of 0.9 ng/L
• The price of erbium is approximately $650 per kilogram. Recent advances in ion-exchange extraction are bringing the price down while increasing uses of the element drive the price up.

Summary of Erbium Properties

The melting point of erbium is 159°C, the boiling point is 2863°C, specific gravity is 9.066 (25°C), and valence is 3. Pure erbium metal is soft and malleable with a bright silvery metallic luster. The metal is fairly stable in air.

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Ytterbium Facts - Yb Element

By Anne Marie Helmenstine, Ph.D.

Uses of Erbium

• Recent studies indicate erbium may help stimulate metabolism. If the element has a biological function, it has yet to be identified. The pure metal is slightly toxic, while the compounds tend to be non-toxic to humans. The highest concentration of erbium in the human body is in bones.
• Erbium is used as a neutron absorber in the nuclear industry.
• It may be added to other metals to lower hardness and improve workability. In particular, it is a common addition to vanadium to make it softer.
• Erbium oxide is used as a pink colorant in glass and porcelain glaze. It is also used to add a pink color to cubic zirconia.
• The same pink ion used in glass and porcelain, Er³⁺, is fluorescent and appears to glow under daylight and fluorescent light. Erbium's interesting optical properties make it useful for lasers (e.g., dental lasers) and optical fibers.
• Like related rare earth, erbium shows sharp absorption spectra bands in the near-infrared, visible, and ultraviolet light.

Sources of Erbium

Erbium occurs in several minerals, along with other rare earth elements. These minerals include gadolinite, euxenite, fergusonite, polycrase, xenotime, and blomstrandine. Following other purification processes, erbium is isolated from similar elements into the pure metal by heating erbium oxide or erbium salts with calcium at 1450 °C in an inert argon atmosphere.

Isotopes: Natural erbium is a mix of six stable isotopes. 29 radioactive isotopes are also recognized.

Element Classification: Rare Earth (Lanthanide)

Density (g/cc): 9.06

Melting Point (K): 1802

Boiling Point (K): 3136

Appearance: soft, malleable, silvery metal

Atomic Radius (pm): 178

Atomic Volume (cc/mol): 18.4

Covalent Radius (pm): 157

Ionic Radius: 88.1 (+3e)

Specific Heat (@20°C J/g mol): 0.168

Evaporation Heat (kJ/mol): 317

Pauling Negativity Number: 1.24

First Ionizing Energy (kJ/mol): 581

Oxidation States: 3

Lattice Structure: Hexagonal

Lattice Constant (Å): 3.560

Lattice C/A Ratio: 1.570

Erbium Element References

• Emsley, John (2001). "Erbium". Nature's Building Blocks: An A-Z Guide to the Elements. Oxford, England, UK: Oxford University Press. pp. 136–139. 
• Patnaik, Pradyot (2003). Handbook of Inorganic Chemical Compounds. McGraw-Hill. pp. 293–295.
• Los Alamos National Laboratory (2001)
• Crescent Chemical Company (2001)
• Lange's Handbook of Chemistry (1952)
• CRC Handbook of Chemistry & Physics (18th Ed.)