Erbium

Erbium produces a characteristic pink-red colour in glass and is critically important for optical fibre communications, erbium-doped fibre amplifiers (EDFAs) boost light signals over long-distance internet cables, enabling the global optical fibre network.

• Atomic Number6868 protons, 68 electrons
• Atomic Mass167.26 u68× heavier than hydrogen
• State at Room TempSolidSolid
• Density9.07 g/cm³
• Melting / Boiling1528.8°C / 2867.8°C
• Discovered1843

What is Erbium?

Erbium is a lanthanide rare earth metal with 68 protons. Erbium-doped fibre amplifiers amplify light signals at 1550 nm: the wavelength most important for long-distance optical communications. The amplifier works by pumping energy into erbium atoms with a laser, then stimulating them to emit photons at the exact signal wavelength. Without EDFAs, trans-oceanic internet cables would not function. Named after Ytterby, Sweden.

Fact Erbium is element 68 in the periodic table, symbol Er. As a lanthanide, it is part of the group of 15 elements sharing very similar chemistry, formed by the filling of the 4f electron subshell. All lanthanides form stable +3 ions and are found together in rare earth mineral deposits.

Where you find Erbium

On Earth

Erbium is found alongside other rare earth elements in minerals such as monazite, bastnäsite and xenotime. China produces the vast majority of world supply, with smaller contributions from Australia, the United States, Russia and India. It is never found as a free metal in nature.

• Monazite and bastnäsite. The primary rare earth minerals that contain Erbium.
• Ion-adsorption clays. Certain clay deposits in southern China are particularly rich in heavier lanthanides including Erbium.

How we use Erbium

Erbium-doped fibre amplifiers amplify light signals at 1550 nm: the wavelength most important for long-distance optical communications. The amplifier works by pumping energy into erbium atoms with a laser, then stimulating them to emit photons at the exact signal wavelength. Without EDFAs, trans-oceanic internet cables would not function. Named after Ytterby, Sweden.

Did you know? Erbium was one of the last lanthanides to be isolated in pure form. The extraordinary chemical similarity between adjacent lanthanides made separation extraordinarily difficult until ion exchange chromatography was developed in the 1940s.

How it was discovered

Erbium was identified and separated from the mixture of rare earth elements found in minerals from Ytterby, Sweden and other locations, through painstaking fractional crystallisation and spectroscopic analysis over many decades in the 19th century.

Deeper dive: erbium and rare earth supply chains

The lanthanides, often called rare earth elements, are critically important for clean energy technologies. Neodymium and praseodymium go into the powerful magnets in EV motors and wind turbines. Dysprosium improves those magnets at high temperatures. Lanthanum and cerium go into NiMH batteries, catalysts and glass. Europium and terbium provide red and green in LED phosphors. This means that the global transition to clean energy depends heavily on rare earth elements, and their supply is dominated by China, which produces over 60% of the world's rare earth output. Concerns about supply security have spurred investment in rare earth mining projects in Australia, Canada, the USA and elsewhere.

Moving to 69 protons brings us to the next element on the periodic table.