Holmium
Definition and meaning of Holmium in chemistry.
Holmium is a chemical element with the symbol Ho and atomic number 67. It is a relatively soft and malleable silvery-white metal belonging to the lanthanide series. Although it is stable in dry air at room temperature, it rapidly oxidizes in moist air and at elevated temperatures.
In more detail
Holmium occurs naturally in minerals such as gadolinite and monazite and is commercially isolated by ion-exchange techniques. Sitting in the f-block of the periodic table, it possesses the highest magnetic moment of any naturally occurring element, giving it unique magnetic properties. When subjected to a magnetic field, it heavily concentrates the magnetic flux, making it highly valuable for creating artificial magnetic poles. Chemically, it behaves like other heavy lanthanides, forming compounds almost exclusively in the +3 oxidation state. It burns in air to form holmium oxide (Ho2O3), which exhibits striking color changes depending on the lighting conditions, appearing yellow in natural daylight and fiery orange under trichromatic fluorescent light. Holmium also has an unusually high ability to absorb neutrons, which drives its use in specialized nuclear control applications.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Ho |
| Atomic number | 67 |
| Atomic mass | 164.93 u |
| Category | Lanthanide |
| State at room temperature | Solid |
| Magnetic moment | 10.6 µB (highest of any element) |
| Year discovered | 1878 |
Holmium is used in yttrium-iron-garnet (YIG) and yttrium-lanthanum-fluoride (YLF) solid-state lasers, which operate at eye-safe wavelengths suitable for medical and dental surgical procedures.
Frequently asked questions
What makes holmium unique among elements?
It possesses the highest magnetic strength (magnetic moment) of any naturally occurring element, making it ideal for specialized magnetic applications.
How is holmium used in medicine?
Holmium lasers emit light at a wavelength that is highly absorbed by water, making them excellent for precise tissue cutting in urological and dental surgeries.