Periodic Table -> Holmium
Holmium DetailsHolmium Symbol:
HoHolmium Atomic Number:
67Holmium Atomic Weight:
164.93What is Holmium?
Holmium (atomic number 67, symbol Ho)
is a rare earth element, which is part of the lanthanide series. It was in 1878 when its oxide was extracted from earth ores, and holmium was named after Stockholm, Sweden. The element was discovered by the Swedish chemist Per Theodor Cleve, and he employed the same method used by Mosander to discover terbium, erbium, and lanthanum. Cleve was looking for impurities in oxides, starting with the oxide of erbium erbia. After removing contaminants and further processing, two new materials were formed, one was green in color, and the other was brown. Cleve named the green one thulia and the brown one holmia. Thulia is thulium oxide while holmia is holmium oxide. The absorption spectrum of holmium was previously observed by the Swiss chemists M. Delafontaine and J. L. Soret.
In terms of properties, Holmium is silvery white in color and relatively malleable and soft. It is not found in pure form in nature because holmium is too reactive; however, it is relatively stable at room temperature and in dry air when isolated. Holmium rusts easily when reacting with water, and when heated, it burns in air. At higher temperatures and in moist air, holmium oxidizes and forms a yellowish-colored oxide. Holmium has a bright silvery, metallic luster in pure form. The lightning conditions make holmium appear differently colored. It has a tannish yellow coloration in daylight while under trichromatic light, it looks like erbium oxide and is orange red.
This element is found in the composition of minerals like gadolinite and monazite, with ion exchange techniques being used to extract holmium from monazite. In laboratory conditions and in nature, the compounds of holmium contain Ho (III) ions and are trivalently oxidized. There is one stable isotope of holmium – holmium-165. Radioactive isotopes have been discovered as well, and holmium-163 is the most stable of them. Its half-life is 4570 years.
This element is also characterized by high magnetic strength, and it is actually the highest of all elements. Because of this, holmium is used to make the polepieces of strong static magnets. Absorbing nuclear-fission bred neutrons, holmium is employed in nuclear control rods as well. Holmium oxide has application as yellow gas coloring. The element is used in solid-state lasers produced for microwave equipment. The latter is made for different dental and medical lasers and is safe for the eyes. Holmium lasers are used in fiber-optical, dental, and medical applications.
In addition, the element is a colorant for glass and cubic zirconia, giving red or yellow coloring. Glass that contains holmium oxide solutions or holmium oxide has sharp peaks in optical absorption. They are in the spectral range 200 – 900 nm. The long-lived and radioactive Ho-166m1 is used to calibrate gamma ray spectrometers.
While holmium is a rare earth element, it is twenty times more abundant than silver. It is not found uncombined in nature and global production is about ten tonnes a year, with the major mining sites being in Sri Lanka, India, Brazil, the United States, China, and Australia.
This element does not have any biological role and is among the least abundant elements found in our bodies. Although holmium has a low acute toxic rating, it acts to stimulate metabolism. Is poses no environmental threat to animal and plant life.
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