Holmium#Chemical properties

Holmium is the eleventh member of the lanthanide series. In the periodic table, it appears in period 6, between the lanthanides dysprosium to its left and erbium to its right, and above the actinide einsteinium.

With a boiling point of {{convert|3000|K|C F|0}}, holmium is the sixth most volatile lanthanide after ytterbium, europium, samarium, thulium and dysprosium. At standard temperature and pressure, holmium, like many of the second half of the lanthanides, normally assumes a hexagonally close-packed (hcp) structure.{{Cite journal |last1=Strandburg |first1=D. L. |last2=Legvold |first2=S. |last3=Spedding |first3=F. H. |date=1962-09-15 |title=Electrical and Magnetic Properties of Holmium Single Crystals |url=https://link.aps.org/doi/10.1103/PhysRev.127.2046 |journal=Physical Review |volume=127 |issue=6 |pages=2046–2051 |doi=10.1103/PhysRev.127.2046|bibcode=1962PhRv..127.2046S |url-access=}} Its 67 electrons are arranged in the configuration [Xe] 4f¹¹ 6s², so that it has thirteen valence electrons filling the 4f and 6s subshells.{{Cite web |title=Holmium (Ho) - Periodic Table |url=https://www.periodictable.one/element/67 |access-date=2024-06-02 |website=www.periodictable.one |language=en}}

Holmium, like all of the lanthanides, is paramagnetic at standard temperature and pressure.{{cite book|last1=Cullity|first1=B. D.|last2=Graham|first2=C. D.|year=2005|page=172|title=Introduction to Magnetic Materials}} However, holmium is ferromagnetic at temperatures below {{convert|19|K|C F}}.{{cite book|title=Introduction to magnetism and magnetic materials|author=Jiles, David|page=228|date=1998}} It has the highest magnetic moment ({{val|10.6|u=μ_B}}) of any naturally occurring element and possesses other unusual magnetic properties. When combined with yttrium, it forms highly magnetic compounds.

Holmium metal tarnishes slowly in air, forming a yellowish oxide layer that has an appearance similar to that of iron rust. It burns readily to form holmium(III) oxide:{{Cite journal |last=Wahyudi |first=Tatang |date=2015 |title=Reviewing the properties of rare earth element-bearing minerals, rare-earth elements and cerium oxide compound |url=https://jurnal.tekmira.esdm.go.id/index.php/imj/article/view/293 |journal=Indonesian Mining Journal |language=en |volume=18 |issue=2 |pages=92–108 |doi=10.30556/imj.Vol18.No2.2015.293 |doi-broken-date=1 November 2024 |issn=2527-8797}}

:4 Ho + 3 O₂ → 2 Ho₂O₃

It is a relatively soft and malleable element that is fairly corrosion-resistant and chemically stable in dry air at standard temperature and pressure. In moist air and at higher temperatures, however, it quickly oxidizes, forming a yellowish oxide.{{Cite journal |last=Phillips |first=W. L. |date=1964-08-01 |title=Oxidation of several lanthanide elements |url=https://dx.doi.org/10.1016/0022-5088%2864%2990056-6 |journal=Journal of the Less Common Metals |language=en |volume=7 |issue=2 |pages=139–143 |doi=10.1016/0022-5088(64)90056-6 |issn=0022-5088 |url-access=subscription}} In pure form, holmium possesses a metallic, bright silvery luster.

Holmium is quite electropositive: on the Pauling electronegativity scale, it has an electronegativity of 1.23.{{cite web |last1=Winter |first1=Mark J. |title=Holmium - 67Ho: electronegativity |url=https://winter.group.shef.ac.uk/webelements/holmium/electronegativity.html#:~:text=Holmium%20%2D%2067Ho%3A%20electronegativity&text=The%20first%20scale%20of%20electronegativity,)%20to%203.98%20(fluorine). |website=WebElements |publisher=University of Sheffield |access-date=4 August 2023}} It is generally trivalent. It reacts slowly with cold water and quickly with hot water to form holmium(III) hydroxide:{{Cite journal |last1=An |first1=Tao |last2=Dou |first2=Chunyue |last3=Ju |first3=Jinning |last4=Wei |first4=Wenlong |last5=Ji |first5=Quanzeng |date=2019-06-01 |title=Microstructure, morphology, wettability and mechanical properties of Ho₂O₃ films prepared by glancing angle deposition |url=https://www.sciencedirect.com/science/article/pii/S0042207X19302428 |journal=Vacuum |language=en |volume=164 |pages=405–410 |doi=10.1016/j.vacuum.2019.03.057 |bibcode=2019Vacuu.164..405A |s2cid=133466738 |issn=0042-207X |url-access=subscription}}

:2 Ho (s) + 6 H₂O (l) → 2 Ho(OH)₃ (aq) + 3 H₂ (g)

Holmium metal reacts with all the stable halogens:

:2 Ho (s) + 3 F₂ (g) → 2 HoF₃ (s) [pink]

:2 Ho (s) + 3 Cl₂ (g) → 2 HoCl₃ (s) [yellow]

:2 Ho (s) + 3 Br₂ (g) → 2 HoBr₃ (s) [yellow]

:2 Ho (s) + 3 I₂ (g) → 2 HoI₃ (s) [yellow]

Holmium dissolves readily in dilute sulfuric acid to form solutions containing the yellow Ho(III) ions, which exist as a [Ho(OH₂)₉]³⁺ complexes:{{cite web| url =https://www.webelements.com/holmium/chemistry.html| title =Chemical reactions of Holmium| publisher=Webelements| access-date=2009-06-06}}

:2 Ho (s) + 3 H₂SO₄ (aq) → 2 Ho³⁺ (aq) + 3 {{chem|SO|4|2-}} (aq) + 3 H₂ (g)

As with many lanthanides, holmium is usually found in the +3 oxidation state, forming compounds such as holmium(III) fluoride (HoF₃) and holmium(III) chloride (HoCl₃). Holmium in solution is in the form of Ho³⁺ surrounded by nine molecules of water. Holmium dissolves in acids.{{cite book|last=Emsley|first=John|title=Nature's Building Blocks|page=226|date=2011}} However, holmium is also found to exist in +2, +1 and 0 oxidation states.{{Cite web |title=Periodic Table of Elements: Los Alamos National Laboratory |url=https://periodic.lanl.gov/67.shtml |access-date=2024-06-02 |website=periodic.lanl.gov}}

{{further|Isotopes of holmium}}

The isotopes of holmium range from ¹⁴⁰Ho to ¹⁷⁵Ho. The primary decay mode before the most abundant stable isotope, ¹⁶⁵Ho, is positron emission, and the primary mode after is beta minus decay. The primary decay products before ¹⁶⁵Ho are terbium and dysprosium isotopes, and the primary products after are erbium isotopes.

Natural holmium consists of one primordial isotope, holmium-165; it is the only isotope of holmium that is thought to be stable, although it is predicted to undergo alpha decay to terbium-161 with a very long half-life.{{cite journal |last1=Belli |first1=P. |last2=Bernabei |first2=R. |last3=Danevich |first3=F. A. |last4=Incicchitti |first4=A. |last5=Tretyak |first5=V. I. |display-authors=3 |title=Experimental searches for rare alpha and beta decays |journal=European Physical Journal A |date=2019 |volume=55 |issue=8 |pages=140–1–140–7 |doi=10.1140/epja/i2019-12823-2 |issn=1434-601X |arxiv=1908.11458|bibcode=2019EPJA...55..140B |s2cid=201664098 }} Of the 35 synthetic radioactive isotopes that are known, the most stable one is holmium-163 (¹⁶³Ho), with a half-life of 4570 years.{{Cite journal |last1=Naumann |first1=R. A. |last2=Michel |first2=M. C. |last3=Power |first3=J. L. |title=Preparation of long-lived holmium-163 |date=September 1960 |osti=4120223 |journal=Journal of Inorganic and Nuclear Chemistry |language=en |volume=15 |issue=1–2 |pages=195–196 |doi=10.1016/0022-1902(60)80035-8}} All other radioisotopes have ground-state half-lives not greater than 1.117 days, with the longest, holmium-166 (¹⁶⁶Ho) having a half-life of 26.83 hours,{{Cite journal |last=Suzuki |first=Yuka S |year=1998 |title=Biodistribution and kinetics of holmium-166-chitosan complex (DW-166HC) in rats and mice. |url=https://jnm.snmjournals.org/content/jnumed/39/12/2161.full.pdf |journal=Journal of Nuclear Medicine |volume=39 |issue=12 |pages=2161–2166|pmid=9867162 }} and most have half-lives under 3 hours.

^166m1Ho has a half-life of around 1200 years.{{Cite journal |last1=Klaassen |first1=Nienke J. M. |last2=Arntz |first2=Mark J. |last3=Gil Arranja |first3=Alexandra |last4=Roosen |first4=Joey |last5=Nijsen |first5=J. Frank W. |date=2019-08-05 |title=The various therapeutic applications of the medical isotope holmium-166: a narrative review |journal=EJNMMI Radiopharmacy and Chemistry |volume=4 |issue=1 |pages=19 |doi=10.1186/s41181-019-0066-3 |issn=2365-421X |pmid=31659560|pmc=6682843 |doi-access=free }} The high excitation energy, resulting in a particularly rich spectrum of decay gamma rays produced when the metastable state de-excites, makes this isotope useful as a means for calibrating gamma ray spectrometers.{{Cite web |last=Oliveira |first=Bernardes, Estela Maria de |date=2001-01-01 |title=Holmium-166m: multi-gamma standard to determine the activity of radionuclides in semiconductor detectors |url=https://inis.iaea.org/search/search.aspx?orig_q=RN:43130653 |language=Portuguese}}

Image:Holmium(III) oxide.jpg, left: natural light, right: under a cold-cathode fluorescent lamp]]

Holmium(III) oxide is the only oxide of holmium. It changes its color depending on the lighting conditions. In daylight, it has a yellowish color. Under trichromatic light, it appears orange red, almost indistinguishable from the appearance of erbium oxide under the same lighting conditions.{{Cite book |last1=Ganjali |first1=Mohammad Reza |title=Lanthanides Series Determination by Various Analytical Methods |last2=Gupta |first2=Vinod Kumar |last3=Faridbod |first3=Farnoush |last4=Norouzi |first4=Parviz |date=2016-02-25 |page=27}} The color change is related to the sharp emission lines of trivalent holmium ions acting as red phosphors.{{cite journal| doi=10.1246/cl.2008.762| title=Hydrothermal Synthesis of GdVO₄:Ho³⁺ Nanorods with a Novel White-light Emission| date=2008| last1=Su| first1=Yiguo| journal=Chemistry Letters| volume=37| pages=762–763| issue=7| last2=Li| first2=Guangshe| last3=Chen| first3=Xiaobo| last4=Liu| first4=Junjie| last5=Li| first5=Liping}} Holmium(III) oxide appears pink under a cold-cathode fluorescent lamp.

Other chalcogenides are known for holmium. Holmium(III) sulfide has orange-yellow crystals in the monoclinic crystal system, with the space group P2₁/m (No. 11).{{Cite book |chapter-url=https://link.springer.com/chapter/10.1007%2F10681735_623 |chapter=Ho₂S₃: crystal structure, physical properties |access-date=2021-06-22 |archive-date=2018-09-01 |archive-url=https://web.archive.org/web/20180901182621/https://link.springer.com/chapter/10.1007/10681735_623 |url-status=live|doi=10.1007/10681735_623|title=Non-Tetrahedrally Bonded Binary Compounds II |series=Landolt-Börnstein - Group III Condensed Matter |year=2000 |volume=41D |pages=1–3 |publisher=Springer |isbn=3-540-64966-2 }} Under high pressure, holmium(III) sulfide can form in the cubic and orthorhombic crystal systems.{{cite book|first1=E. Yu |last1=Tonkov|title=Compounds and Alloys Under High Pressure A Handbook|year=1998|page=272}} It can be obtained by the reaction of holmium(III) oxide and hydrogen sulfide at {{convert|1598|K|C F}}.{{cite book|editor1=G. Meyer|editor2= Lester R. Morss|title=Synthesis of Lanthanide and Actinide Compounds|year=1991|page=329}} Holmium(III) selenide is also known. It is antiferromagnetic below 6 K.{{Cite journal |last1=Bespyatov |first1=M. A. |last2=Musikhin |first2=A. E. |last3=Naumov |first3=V. N. |last4=Zelenina |first4=L. N. |last5=Chusova |first5=T. P. |last6=Nikolaev |first6=R. E. |last7=Naumov |first7=N. G. |date=2018-03-01 |title=Low-temperature thermodynamic properties of holmium selenide (2:3) |url=https://www.sciencedirect.com/science/article/pii/S0021961417303804 |journal=The Journal of Chemical Thermodynamics |language=en |volume=118 |pages=21–25 |doi=10.1016/j.jct.2017.10.013 |bibcode=2018JChTh.118...21B |issn=0021-9614 |url-access=subscription}}

All four trihalides of holmium are known. Holmium(III) fluoride is a yellowish powder that can be produced by reacting holmium(III) oxide and ammonium fluoride, then crystallising it from the ammonium salt formed in solution.{{Cite book |title=Riedel, moderne anorganische Chemie |date=2012 |publisher=De Gruyter |others=Erwin Riedel, Christoph Janiak, Hans-Jürgen Meyer}} Holmium(III) chloride can be prepared in a similar way, with ammonium chloride instead of ammonium fluoride.{{Cite web |title=Holmium chloride {{!}} 10138-62-2 |url=https://www.chemicalbook.com/ChemicalProductProperty_EN_CB0255341.htm |access-date=2023-08-09 |website=ChemicalBook |language=en}} It has the YCl₃ layer structure in the solid state.{{Cite book |last=Wells |first=A. F. |title=Structural inorganic chemistry |page=421}} These compounds, as well as holmium(III) bromide and holmium(III) iodide, can be obtained by the direct reaction of the elements:

:2 Ho + 3 X₂ → 2 HoX₃

In addition, holmium(III) iodide can be obtained by the direct reaction of holmium and mercury(II) iodide, then removing the mercury by distillation.{{cite journal| doi = 10.1021/ic50018a015| title = Preparation and crystal data for lanthanide and actinide triiodides| year = 1964| last1 = Asprey| first1 = L. B.| last2 = Keenan| first2 = T. K.| last3 = Kruse| first3 = F. H.| journal = Inorganic Chemistry| volume = 3| issue = 8| pages = 1137–1141| url = https://digital.library.unt.edu/ark:/67531/metadc867868/ |url-access=subscription}}

{{See also|Organolanthanide chemistry}}

Organoholmium compounds are very similar to those of the other lanthanides, as they all share an inability to undergo π backbonding. They are thus mostly restricted to the mostly ionic cyclopentadienides (isostructural with those of lanthanum) and the σ-bonded simple alkyls and aryls, some of which may be polymeric.Greenwood and Earnshaw, pp. 1248{{ndash}}1249

Holmium ({{lang|la|Holmia}}, Latin name for Stockholm) was discovered by the Swiss chemists Jacques-Louis Soret and Marc Delafontaine in 1878 who noticed the aberrant spectrographic emission spectrum of the then-unknown element (they called it "Element X").{{cite journal|title = Sur les spectres d'absorption ultra-violets des terres de la gadolinite|author = Jacques-Louis Soret|journal = Comptes rendus de l'Académie des sciences|volume = 87|pages = 1062|date = 1878|url = http://gallica.bnf.fr/ark:/12148/bpt6k3043m/f1124.table}}

{{cite journal|title = Sur le spectre des terres faisant partie du groupe de l'yttria

|author = Jacques-Louis Soret|journal = Comptes rendus de l'Académie des sciences

|volume = 89|pages = 521|date = 1879|url = https://gallica.bnf.fr/ark:/12148/bpt6k3046j/f550.table}}

The Swedish chemist Per Teodor Cleve also independently discovered the element while he was working on erbia earth (erbium oxide). He was the first to isolate impure oxide of the new element.{{cite web |title=Holmium |url=https://www.rsc.org/periodic-table/element/67/holmium |website=Royal Society of Chemistry|date= 2020 |access-date=4 January 2020}}{{cite journal |last1=Marshall |first1=James L. Marshall |last2=Marshall |first2=Virginia R. Marshall |title=Rediscovery of the elements: The Rare Earths–The Confusing Years |journal=The Hexagon |date=2015 |pages=72–77 |url=http://www.chem.unt.edu/~jimm/REDISCOVERY%207-09-2018/Hexagon%20Articles/rare%20earths%20II.pdf |access-date=30 December 2019}}{{cite book |last1=Weeks |first1=Mary Elvira |title=The discovery of the elements |date=1956 |publisher=Journal of Chemical Education |page=710}} Using the method developed by the Swedish chemist Carl Gustaf Mosander, Cleve first removed all of the known contaminants from erbia. The result of that effort was two new materials, one brown and one green. He named the brown substance holmia (after the Latin name for Cleve's home town, Stockholm) and the green one thulia. Holmia was later found to be the holmium oxide, and thulia was thulium oxide. The pure oxide was only isolated in 1911 and the metal in 1939 by Heinrich Bommer.{{Cite book |last=Sicius |first=Hermann |url=https://link.springer.com/10.1007/978-3-662-68921-9 |title=Handbook of the Chemical Elements |date=2024 |publisher=Springer Berlin Heidelberg |isbn=978-3-662-68920-2 |location=Berlin, Heidelberg |language=en |doi=10.1007/978-3-662-68921-9}}{{rp|959}}{{Cite journal|last=Bommer |first=Heinrich |url=https://onlinelibrary.wiley.com/doi/abs/10.1002/zaac.19392420307 |journal=Zeitschrift für anorganische und allgemeine Chemie|volume=242|issue=3|title=Kristallstruktur und magnetisches Verhalten des metallischen Holmiums |date=1939 |pages=277–280 |language=de |doi=10.1002/zaac.19392420307|url-access=subscription }}

In the English physicist Henry Moseley's classic paper on atomic numbers, holmium was assigned the value 66. The holmium preparation he had been given to investigate had been impure, dominated by neighboring dysprosium. He would have seen x-ray emission lines for both elements, but assumed that the dominant ones belonged to holmium, instead of the dysprosium impurity.{{cite journal|last1=Egdell|first1=Russell G.|last2=Bruton|first2=Elizabeth|date=2020|title=Henry Moseley, X-ray spectroscopy and the periodic table|journal=Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences|volume=378|issue=2180|doi=10.1002/chem.202004775|pmid=32811359|doi-access=free}}

File:Gadolinitas.jpg]]

Like all the other rare-earth elements, holmium is not naturally found as a free element. It occurs combined with other elements in gadolinite, monazite and other rare-earth minerals. No holmium-dominant mineral has yet been found. The main mining areas are China, United States, Brazil, India, Sri Lanka, and Australia with reserves of holmium estimated as 400,000 tonnes. The annual production of holmium metal is of about 10 tonnes per year.{{Cite web |title=Ho - Holmium |url=https://mmta.co.uk/metals/ho/ |access-date=5 December 2022 |publisher=MMTA |language=}}

Holmium makes up 1.3 parts per million of the Earth's crust by mass.ABUNDANCE OF ELEMENTS IN THE EARTH’S CRUST AND IN THE SEA, CRC Handbook of Chemistry and Physics, 97th edition (2016–2017), p. 14-17 Holmium makes up 1 part per million of the soils, 400 parts per quadrillion of seawater, and almost none of Earth's atmosphere, which is very rare for a lanthanide.{{cite book|last=Emsley|first=John|title=Nature's Building Blocks|page=225|date=2011}} It makes up 500 parts per trillion of the universe by mass.{{cite web|url=http://www.webelements.com/periodicity/abundance_universe/.|title=WebElements Periodic Table » Periodicity » Abundance in the universe » periodicity|first=Mark Winter, University of Sheffield and WebElements|last=Ltd|website=www.webelements.com|access-date=27 March 2018|archive-url=https://web.archive.org/web/20170929183039/https://www.webelements.com/periodicity/abundance_universe/|archive-date=2017-09-29}}

Holmium is commercially extracted by ion exchange from monazite sand (0.05% holmium), but is still difficult to separate from other rare earths. The element has been isolated through the reduction of its anhydrous chloride or fluoride with metallic calcium. Its estimated abundance in the Earth's crust is 1.3 mg/kg. Holmium obeys the Oddo–Harkins rule: as an odd-numbered element, it is less abundant than both dysprosium and erbium. However, it is the most abundant of the odd-numbered heavy lanthanides. Of the lanthanides, only promethium, thulium, lutetium and terbium are less abundant on Earth. The principal current source are some of the ion-adsorption clays of southern China. Some of these have a rare-earth composition similar to that found in xenotime or gadolinite. Yttrium makes up about two-thirds of the total by mass; holmium is around 1.5%.{{cite book|last =Patnaik|first =Pradyot|date = 2003|title =Handbook of Inorganic Chemical Compounds|publisher = McGraw-Hill|pages = 338–339| isbn =0-07-049439-8|url= https://books.google.com/books?id=Xqj-TTzkvTEC&pg=PA338|access-date = 2009-06-06|archive-url=https://archive.org/details/handbookofinorga0000patn/page/n3/mode/2up|archive-date=2023-06-14}} Holmium is relatively inexpensive for a rare-earth metal with the price about 1000 USD/kg.{{cite news| publisher = USGS| title =Rare-Earth Metals| author = James B. Hedrick| access-date = 2009-06-06| url =http://minerals.usgs.gov/minerals/pubs/commodity/rare_earths/740798.pdf}}

File:HoOxideSolution.jpg as an optical calibration standard]]

Glass containing holmium oxide and holmium oxide solutions (usually in perchloric acid) have sharp optical absorption peaks in the spectral range 200 to 900 nm. They are therefore used as a calibration standard for optical spectrophotometers.{{cite journal | last=Allen | first=David W. | title=Holmium oxide glass wavelength standards | journal=Journal of Research of the National Institute of Standards and Technology | volume=112 | issue=6 | year=2007 | pages=303–306 | issn=1044-677X | doi=10.6028/jres.112.024 | pmid=27110474 | pmc=4655923 }}{{cite journal | last1=Travis | first1=John C. | last2=Zwinkels | first2=Joanne C. | last3=Mercader | first3=Flora | display-authors=etal | title=An International Evaluation of Holmium Oxide Solution Reference Materials for Wavelength Calibration in Molecular Absorption Spectrophotometry | journal=Analytical Chemistry | volume=74 | issue=14 | date=2002-06-05 | issn=0003-2700 | doi=10.1021/ac0255680 | pages=3408–3415| pmid=12139047 }}{{cite journal|url=http://www.clinchem.org/cgi/reprint/10/12/1117.pdf| journal =Clinical Chemistry| volume = 10| date =1964|title =Uses for a Holmium Oxide Filter in Spectrophotometry| author = R. P. MacDonald| pmid=14240747| issue=12|pages=1117–20| doi =10.1093/clinchem/10.12.1117 |url-access=subscription}} The radioactive but long-lived ^166m1Ho is used in calibration of gamma-ray spectrometers.{{cite journal|title = The absolute counting of ^166mHo, ⁵⁸Co and ⁸⁸Y|author = Ming-Chen Yuan|author2 = Jeng-Hung Lee|author3 = Wen-Song Hwang|name-list-style = amp|doi = 10.1016/S0969-8043(01)00226-3 |pmid = 11839051|journal = Applied Radiation and Isotopes

|volume = 56|issue = 1–2|pages = 429–434|date = 2002| bibcode=2002AppRI..56..429Y }}

Holmium is used to create the strongest artificially generated magnetic fields, when placed within high-strength magnets as a magnetic pole piece (also called a magnetic flux concentrator).{{cite journal| journal =IEEE Transactions on Magnetics| volume = 21| date =1985| display-authors = 6| author = R. W. Hoard| title =Field enhancement of a 12.5-T magnet using holmium poles| author2 = S. C. Mance| author3 = R. L. Leber| author4 = E. N. Dalder| author5 = M. R. Chaplin| author6 = K. Blair| author7 = D. H. Nelson| author8 = D. A. Van Dyke| issue=2|pages=448–450| doi=10.1109/tmag.1985.1063692|bibcode = 1985ITM....21..448H | s2cid = 121828376| url = https://digital.library.unt.edu/ark:/67531/metadc1200738/| url-access = subscription}} Holmium is also used in the manufacture of some permanent magnets.

Holmium can act as a sensitizer in sodium yttrium fluoride which takes advantage of its absorption in the NIR-II window. Holmium allows for lanthanide nanomaterials to have tunable emission and excitation in the NIR-II. Under 1143 nm excitation the interfacial energy transfer to other lanthanides allows a redshift in emission for biological applications.{{Cite journal |last=Wang |first=Xusheng |last2=Wu |first2=Wenxiao |last3=Yun |first3=Baofeng |last4=Huang |first4=Liwen |last5=Chen |first5=Zi-Han |last6=Ming |first6=Jiang |last7=Zhai |first7=Fuheng |last8=Zhang |first8=Hongxin |last9=Zhang |first9=Fan |date=2025-01-15 |title=An Emerging Toolkit of Ho3+ Sensitized Lanthanide Nanocrystals with NIR-II Excitation and Emission for in Vivo Bioimaging |url=https://pubs.acs.org/doi/10.1021/jacs.4c16451 |journal=Journal of the American Chemical Society |volume=147 |issue=2 |pages=2182–2192 |doi=10.1021/jacs.4c16451 |issn=0002-7863|url-access=subscription }} This allows deeper penetration than typically used 980 nm and 808 nm lasers.

Holmium-doped yttrium iron garnet (YIG) and yttrium lithium fluoride have applications in solid-state lasers, and Ho-YIG has applications in optical isolators and in microwave equipment (e.g., YIG spheres). Holmium lasers emit at 2.1 micrometres.{{cite journal| title=The holmium laser in urology| journal=Journal of Clinical Laser Medicine & Surgery | pmid=9728125 | volume=16 | issue=1 | date=Feb 1998| pages=13–20| last1=Wollin | first1=T. A. | last2=Denstedt | first2=J. D. | doi=10.1089/clm.1998.16.13 }} They are used in medical, dental, and fiber-optical applications.{{cite book| page = 30| url = https://books.google.com/books?id=F0Bte_XhzoAC&pg=PA32| title = Extractive metallurgy of rare earths| author = C. K. Gupta| author2 = Nagaiyar Krishnamurthy| publisher =CRC Press| date = 2004| isbn =0-415-33340-7}} It is also being considered for usage in the enucleation of the prostate.{{Cite journal |last1=Gilling |first1=Peter J. |last2=Aho |first2=Tevita F. |last3=Frampton |first3=Christopher M. |last4=King |first4=Colleen J. |last5=Fraundorfer |first5=Mark R. |date=2008-04-01 |title=Holmium Laser Enucleation of the Prostate: Results at 6 Years |url=https://www.sciencedirect.com/science/article/pii/S0302283807005933 |journal=European Urology |language=en |volume=53 |issue=4 |pages=744–749 |doi=10.1016/j.eururo.2007.04.052 |pmid=17475395 |issn=0302-2838 |url-access=subscription}}

Since holmium can absorb nuclear fission-bred neutrons, it is used as a burnable poison to regulate nuclear reactors. It is used as a colorant for cubic zirconia, providing pink coloring,{{Cite journal|last=Nassau|first=Kurt|date=Spring 1981|title=Cubic zirconia: An Update.|journal=Gems & Gemology|volume=1|issue=1 |pages=9–19|doi=10.5741/GEMS.17.1.9|bibcode=1981GemG...17....9N |url=https://www.gia.edu/doc/Cubic-Zirconia.pdf}} and for glass, providing yellow-orange coloring.{{Cite journal |last1=El-Batal |first1=Hatem A. |last2=Azooz |first2=Moenis A. |last3=Ezz-El-Din |first3=Fathy M. |last4=El-Alaily |first4=Nagia A. |date=2004-12-20 |title=Interaction of Gamma Rays with Calcium Aluminoborate Glasses Containing Holmium or Erbium |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1151-2916.2001.tb00959.x |journal=Journal of the American Ceramic Society |language=en |volume=84 |issue=9 |pages=2065–2072 |doi=10.1111/j.1151-2916.2001.tb00959.x |url-access=subscription}} In March 2017, IBM announced that they had developed a technique to store one bit of data on a single holmium atom set on a bed of magnesium oxide.{{cite web|url=https://techcrunch.com/2017/03/08/storing-data-in-a-single-atom-proved-possible-by-ibm-researchers/|access-date=2017-03-10|title=Storing data in a single atom proved possible by IBM researchers|website=TechCrunch|last1=Coldeway|first1=Devin|date=March 9, 2017}} With sufficient quantum and classical control techniques, holmium may be a good candidate to make quantum computers.{{Cite journal|last1=Forrester|first1=Patrick Robert|last2=Patthey|first2=François|last3=Fernandes|first3=Edgar|last4=Sblendorio|first4=Dante Phillipe|last5=Brune|first5=Harald|last6=Natterer|first6=Fabian Donat|date=2019-11-19|title=Quantum state manipulation of single atom magnets using the hyperfine interaction|journal=Physical Review B|language=en|volume=100|issue=18|pages=180405|doi=10.1103/PhysRevB.100.180405| arxiv=1903.00242 |issn=2469-9950|bibcode=2019PhRvB.100r0405F|doi-access=free}}

Holmium is used in the medical field, particularly in laser surgery for procedures such as kidney stone removal and prostate treatment, due to its precision and minimal tissue damage.{{cite web |url=https://www.stanfordmaterials.com/blog/holmium-properties-and-applications.html |title=Holmium: Properties and Applications |last=Loewen |first=Eric |website=Stanford Advanced Materials |access-date=Oct 23, 2024}}{{cite journal |last1=Younis |first1=Zaid |last2=Ayyed |first2=Atheer |title=Influence of stone location on rate of stone clearance and complication for holmium laser lithotripsy |journal=International Journal of Urology Research |volume=6 |issue=1 |year=2024 |pages=84–90 |doi=10.33545/26646617.2024.v6.i1b.38}} Its isotope, holmium-166, is applied in targeted cancer therapies, especially for liver cancer,{{cite journal |last1=Kuhnel |first1=Christian |last2=Kohler |first2=Alexander |year=2024 |title=Clinical Results of Holmium-166 Radioembolization with Personalized Dosimetry for the Treatment of Hepatocellular Carcinoma |journal=J. Pers. Med. |volume=14 |issue=7 |page=747 |doi=10.3390/jpm14070747|doi-access=free |pmid=39064001 |pmc=11278198 }} and it also enhances MRI imaging as a contrast agent.{{cite journal |last1=Maat |first1=Gerrit |last2=Seevinck |first2=Peter |year=2013 |title=MRI-based biodistribution assessment of holmium-166 poly(L-lactic acid) microspheres after radioembolisation |journal=European Radiology |volume=23 |issue=3 |pages=827–835 |doi=10.1007/s00330-012-2648-2 |doi-access=free|pmid=23014797 |pmc=3563959 }}

Holmium plays no biological role in humans, but its salts are able to stimulate metabolism.{{cite book| author = C. R. Hammond |title = The Elements, in Handbook of Chemistry and Physics |edition = 81st| publisher =CRC press| date = 2000| isbn = 0-8493-0481-4}} Humans typically consume about a milligram of holmium a year. Plants do not readily take up holmium from the soil. Some vegetables have had their holmium content measured, and it amounted to 100 parts per trillion.{{cite book|last=Emsley|first=John|title=Nature's Building Blocks|page=224|date=2011}} Holmium and its soluble salts are slightly toxic if ingested, but insoluble holmium salts are nontoxic. Metallic holmium in dust form presents a fire and explosion hazard.{{cite journal|last1=Haley|first1= T. J.|last2=Koste|first2= L.|last3= Komesu|first3= N.|last4= Efros|first4= M.|last5= Upham|first5= H. C. |year=1966 |title=Pharmacology and toxicology of dysprosium, holmium, and erbium chlorides |journal=Toxicology and Applied Pharmacology |volume=8 |issue=1 |pages=37–43 |doi=10.1016/0041-008x(66)90098-6 |pmid=5921895|bibcode= 1966ToxAP...8...37H}}{{cite journal |author=Haley, T. J. |year=1965 |title=Pharmacology and toxicology of the rare earth elements |journal=Journal of Pharmaceutical Sciences |volume=54 |issue=5 |pages=663–70 |doi=10.1002/jps.2600540502 |pmid=5321124}}{{cite journal |last1=Bruce|first1= D. W.|last2= Hietbrink|first2= B. E.|last3= Dubois|first3= K. P. |year=1963 |title=The acute mammalian toxicity of rare earth nitrates and oxides |journal=Toxicology and Applied Pharmacology |volume=5 |issue=6 |pages= 750–9|doi=10.1016/0041-008X(63)90067-X |pmid= 14082480|bibcode= 1963ToxAP...5..750B}} Large amounts of holmium salts can cause severe damage if inhaled, consumed orally, or injected. The biological effects of holmium over a long period of time are not known. Holmium has a low level of acute toxicity.{{Cite web |date=2011-04-15 |title=Holmium: Biological Action |url=http://nautilus.fis.uc.pt/st2.5/scenes-e/elem/e06740.html |access-date=2023-03-05 |archive-url=https://web.archive.org/web/20110415162101/http://nautilus.fis.uc.pt/st2.5/scenes-e/elem/e06740.html |archive-date=2011-04-15 }}

• :Category:Holmium compounds
• Period 6 element

{{Reflist|30em}}

• {{cite book|author=Emsley, John|author-link=John Emsley|title=Nature's Building Blocks: An A-Z Guide to the Elements|date=2011|publisher=Oxford University Press|isbn=978-0-19-960563-7|ref=none}}
• {{cite book |last1=Greenwood |first1=Norman N. |last2=Earnshaw |first2=Alan |title=Chemistry of the Elements |date=1997 |publisher=Butterworth-Heinemann |isbn=978-0-08-037941-8 |edition=2nd |ref=none}}
• {{cite book |last1=Stwertka |first1=Albert |title=A guide to the elements |date=1998 |publisher=Oxford University Press |isbn=0-19-508083-1 |edition=2nd |ref=none}}
• {{cite book|last1=Cullity|first1=B. D.|last2=Graham|first2=C. D.|year=2005|title=Introduction to Magnetic Materials|publisher=John Wiley & Sons|isbn=978-1-118-21149-6 |ref=none}}
• {{cite book|title=Introduction to magnetism and magnetic materials|author=Jiles, David|url=https://books.google.com/books?id=axyWXjsdorMC|publisher=CRC Press|date=1998|isbn=0-412-79860-3 |ref=none}}
• {{Cite book |last1=Ganjali |first1=Mohammad Reza |url=https://books.google.com/books?id=WtecBAAAQBAJ&dq=holmium+oxide+under+trichromatic+light&pg=PP1 |title=Lanthanides Series Determination by Various Analytical Methods |last2=Gupta |first2=Vinod Kumar |last3=Faridbod |first3=Farnoush |last4=Norouzi |first4=Parviz |date=2016-02-25 |publisher=Elsevier |isbn=978-0-12-420095-1 |language=en |ref=none}}
• {{cite book|first1=E. Yu |last1=Tonkov|title=Compounds and Alloys Under High Pressure A Handbook|publisher=CRC Press|year=1998|isbn=978-90-5699-047-3|url=https://books.google.com/books?id=q2u4kUX8HsIC&pg=PA272

|ref=none}}

• {{cite book|editor1=G. Meyer|editor2= Lester R. Morss|title=Synthesis of Lanthanide and Actinide Compounds|publisher=Kluwer Academic Publishers|year=1991|isbn=0792310187|url=https://books.google.com/books?id=bnS5elHL2w8C&pg=PA329|ref=none }}
• {{Cite book |title=Riedel, moderne anorganische Chemie |date=2012 |publisher=De Gruyter |others=Erwin Riedel, Christoph Janiak, Hans-Jürgen Meyer |isbn=978-3-11-024900-2 |edition=4. Aufl |location=Berlin |oclc=781540844 |language=de|ref=none}}
• {{Cite book |last=Wells |first=A. F. |title=Structural inorganic chemistry |date=1984 |publisher=Clarendon Press |isbn=9780198553700 |edition=5th |location=Oxford [Oxfordshire] |oclc=8866491|ref=none}}
• {{cite book |last1=Weeks |first1=Mary Elvira |title=The discovery of the elements |date=1956 |publisher=Journal of Chemical Education |location=Easton, PA |url=https://archive.org/details/discoveryoftheel002045mbp |edition=6th|ref=none }}

• R. J. Callow, The Industrial Chemistry of the Lanthanons, Yttrium, Thorium, and Uranium, Pergamon Press, 1967.

{{Commons}}

• [http://www.periodicvideos.com/videos/067.htm Holmium] at The Periodic Table of Videos (University of Nottingham)

{{clear}}

{{Periodic table (navbox)}}

{{Holmium compounds}}

{{Authority control}}

Category:Chemical elements

Category:Chemical elements with hexagonal close-packed structure

Category:Ferromagnetic materials

Category:Lanthanides

Category:Neutron poisons

Category:Reducing agents