Editing Holmium (section)

==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]].

===Physical properties===

With a boiling point of {{convert|3000|K|C F|0}}, holmium is the sixth most [[Volatility (chemistry)|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 [[hexagonal crystal system|hexagonally close-packed (hcp)]] structure.<ref>{{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=subscription}}</ref> Its 67 [[electron]]s are arranged in the configuration [Xe] 4f<sup>11</sup> 6s<sup>2</sup>, so that it has thirteen [[valence electron]]s filling the 4f and 6s subshells.<ref name=":0">{{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}}</ref>

Holmium, like all of the lanthanides, is [[paramagnetic]] at standard temperature and pressure.<ref>{{cite book|last1=Cullity|first1=B. D.|last2=Graham|first2=C. D.|year=2005|page=172|title=Introduction to Magnetic Materials}}</ref> However, holmium is [[ferromagnetic]] at temperatures below {{convert|19|K|C F}}.<ref>{{cite book|title=Introduction to magnetism and magnetic materials|author=Jiles, David|page=228|date=1998}}</ref> It has the highest [[magnetic moment]] ({{val|10.6|u=[[Bohr magneton|''μ''<sub>B</sub>]]}}) of any naturally occurring element<ref name="emsley226" /> and possesses other unusual magnetic properties. When combined with [[yttrium]], it forms highly [[magnetism|magnetic]] compounds.<ref name="appl" />

===Chemical properties===

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]]:<ref>{{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}}</ref>

:4 Ho + 3 O<sub>2</sub> → 2 Ho<sub>2</sub>O<sub>3</sub>

It is a relatively soft and [[Ductility|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 [[oxidation|oxidizes]], forming a yellowish oxide.<ref>{{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}}</ref> 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.<ref name="Win">{{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}}</ref> It is generally trivalent. It reacts slowly with cold water and quickly with hot water to form holmium(III) hydroxide:<ref>{{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 Ho<sub>2</sub>O<sub>3</sub> 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}}</ref>
:2 Ho (s) + 6 H<sub>2</sub>O (l) → 2 Ho(OH)<sub>3</sub> (aq) + 3 H<sub>2</sub> (g)

Holmium metal reacts with all the stable [[halogen]]s:<ref name="Webelements" />
:2 Ho (s) + 3 F<sub>2</sub> (g) → 2 [[Holmium(III) fluoride|HoF<sub>3</sub>]] (s) [pink]

:2 Ho (s) + 3 Cl<sub>2</sub> (g) → 2 [[Holmium(III) chloride|HoCl<sub>3</sub>]] (s) [yellow]

:2 Ho (s) + 3 Br<sub>2</sub> (g) → 2 [[Holmium(III) bromide|HoBr<sub>3</sub>]] (s) [yellow]

:2 Ho (s) + 3 I<sub>2</sub> (g) → 2 [[Holmium(III) iodide|HoI<sub>3</sub>]] (s) [yellow]

Holmium dissolves readily in dilute [[sulfuric acid]] to form [[Solution (chemistry)|solution]]s containing the yellow Ho(III) ions, which exist as a [Ho(OH<sub>2</sub>)<sub>9</sub>]<sup>3+</sup> complexes:<ref name="Webelements">{{cite web| url =https://www.webelements.com/holmium/chemistry.html| title =Chemical reactions of Holmium| publisher=Webelements| access-date=2009-06-06}}</ref>

:2 Ho (s) + 3 H<sub>2</sub>SO<sub>4</sub> (aq) → 2 Ho<sup>3+</sup> (aq) + 3 {{chem|SO|4|2-}} (aq) + 3 H<sub>2</sub> (g)

====Oxidation states====
As with many lanthanides, holmium is usually found in the +3 [[oxidation state]], forming compounds such as [[holmium(III) fluoride]] (HoF<sub>3</sub>) and [[holmium(III) chloride]] (HoCl<sub>3</sub>).  Holmium in solution is in the form of Ho<sup>3+</sup> surrounded by nine molecules of water. Holmium dissolves in [[acid]]s.<ref name="emsley226">{{cite book|last=Emsley|first=John|title=Nature's Building Blocks|page=226|date=2011}}</ref> However, holmium is also found to exist in +2, +1 and 0 oxidation states.<ref>{{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}}</ref><ref name=":0" />

===Isotopes===
{{further|Isotopes of holmium}}

The isotopes of holmium range from <sup>140</sup>Ho to <sup>175</sup>Ho. The primary [[decay mode]] before the most abundant [[stable isotope]], <sup>165</sup>Ho, is [[positron emission]], and the primary mode after is [[beta minus decay]]. The primary [[decay product]]s before <sup>165</sup>Ho are [[terbium]] and [[dysprosium]] isotopes, and the primary products after are [[erbium]] isotopes.<ref name="CRC" />

Natural holmium consists of one [[primordial isotope]], holmium-165;<ref name="emsley226" /> 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.<ref>{{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 }}</ref> Of the 35 [[synthetic element|synthetic]] radioactive isotopes that are known, the most stable one is holmium-163 (<sup>163</sup>Ho), with a half-life of 4570 years.<ref>{{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}}</ref> All other radioisotopes have ground-state half-lives not greater than 1.117 days, with the longest, holmium-166 (<sup>166</sup>Ho) having a half-life of 26.83 hours,<ref>{{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 }}</ref> and most have half-lives under 3 hours.

<sup>166m1</sup>Ho has a half-life of around 1200 years.<ref>{{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 }}</ref> The high excitation energy, resulting in a particularly rich spectrum of decay [[gamma ray]]s produced when the metastable state de-excites, makes this isotope useful as a means for [[Calibration|calibrating]] [[gamma ray spectrometer]]s.<ref>{{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}}</ref>