At A Glance: Er

Atomic Number: 68
Atomic Symbol: Er
Atomic Weight: 167.26
Electron Configuration: [Xe]6s24f12
Atomic Radius: 235 pm (Van der Waals)
Melting Point: 1529 °C
Boiling Point: 2868 °C
Oxidation States:
Uses: Fiber optic data transmission, lasers for medical and dental uses, glass coloration used in sunglasses and decorative crystal glassware.

Content provided by Los Alamos National Laboratory. Used with permission.

Rare earth element - Erbium
Rare earth elements - Erbium
Erbium Spin Video

Photos of rare earth elements used on our site are copyright of Max Whitby and Theodore Gray. Used with permission.

Erbium can be found as an amplifier for fiber optic data transmission (since Erbium fortuitously loses efficiently at 1.55 microns). Lasers based on Erbium have been introduced for medical and dental uses because they are suited to energy delivery without thermal build-up in human tissue. Erbium is also used in glass coloration where its stability ensures that glass formulations using it will be colored pink. It is the only pink colorant truly stable in glass melts and is used in sunglasses and decorative crystal glassware. Erbium is finding nuclear and metallurgical uses. Added to vanadium, for example, erbium lowers the hardness and improves workability.


Erbium is found in the minerals mentioned under dysprosium. In 1842 Mosander separated “yttria” found in the mineral gadolinite, into three fractions which he called yttria, erbia, and terbia. The names erbia and terbia became confused in this early period. After 1860, Mosander’s terbia was known as erbia, and after 1877, the earlier known erbia became terbia. The erbia of this period was later shown to consist of five oxides, now known as erbia, scandia, holmia, thulia and ytterbia. By 1905 Urbain and James independently succeeded in isolating fairly pure Er2O3. Klemm and Bommer first produced reasonably pure erbium metal in 1934 by reducing the anhydrous chloride with potassium vapor.


The pure metal is soft and malleable and has a bright, silvery, metallic luster. As with other rare-earth metals, its properties depend to a certain extent on the impurities present. The metal is fairly stable in air and does not oxidize as rapidly as some of the other rare-earth metals. Naturally occurring erbium is a mixture of six isotopes, all of which are stable. Nine radioactive isotopes of erbium are also recognized. Recent production techniques, using ion-exchange reactions, have resulted in much lower prices of the rare-earth metals and their compounds in recent years. Most of the rare-earth oxides have sharp absorption bands in the visible, ultraviolet, and near infrared. This property, associated with the electronic structure, gives beautiful pastel colors to many of the rare-earth salts.

Sources: Los Alamos National Laboratory; Molycorp

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