Holmium

Holmium has the strongest magnetic moment of any naturally occurring element and is used to create powerful magnetic flux concentrators and in yttrium-iron-garnet lasers used in medicine. Its name comes from Holmia, the Latin name for Stockholm.

• Atomic Number6767 protons, 67 electrons
• Atomic Mass164.93033 u67× heavier than hydrogen
• State at Room TempSolidSolid
• Density8.80 g/cm³
• Melting / Boiling1473.8°C / 2699.8°C
• Discovered1878

What is Holmium?

Holmium is a lanthanide rare earth metal with 67 protons. Holmium is used in specialised lasers for kidney stone removal, laser surgery and fibre optics. It is also used in strong magnets and nuclear reactor control rods. It was discovered spectroscopically in 1878 by Marc Delafontaine and Per Teodor Cleve, working independently in Switzerland and Sweden.

Fact Holmium is element 67 in the periodic table, symbol Ho. 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 Holmium

On Earth

Holmium 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 Holmium.
• Ion-adsorption clays. Certain clay deposits in southern China are particularly rich in heavier lanthanides including Holmium.

How we use Holmium

Holmium is used in specialised lasers for kidney stone removal, laser surgery and fibre optics. It is also used in strong magnets and nuclear reactor control rods. It was discovered spectroscopically in 1878 by Marc Delafontaine and Per Teodor Cleve, working independently in Switzerland and Sweden.

Did you know? Holmium 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

Holmium 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: holmium 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 68 protons brings us to the next element on the periodic table.