Editing Erbium (section)

===Physical properties===
[[Image:Erbium(III)chloride sunlight.jpg|thumb|left|Erbium(III) chloride in sunlight, showing some pink fluorescence of Er<sup>+3</sup> from natural ultraviolet.]]
A [[valence (chemistry)|trivalent]] element, pure erbium [[metal]] is malleable (or easily shaped), soft yet stable in air, and does not [[oxidation|oxidize]] as quickly as some other [[rare-earth metals]]. Its [[Salt (chemistry)|salts]] are rose-colored, and the element has characteristic sharp [[absorption spectra]] bands in [[visible light]], [[ultraviolet]], and near [[infrared]].<ref>{{Cite journal |last1=Humpidge |first1=J. S. |last2=Burney |first2=W. |date=1879-01-01 |title=XIV.—On erbium and yttrium |url=https://pubs.rsc.org/en/content/articlelanding/1879/ct/ct8793500111 |journal=Journal of the Chemical Society, Transactions |language=en |volume=35 |pages=111–117 |doi=10.1039/CT8793500111 |issn=0368-1645}}</ref> Otherwise it looks much like the other rare earths. Its [[sesquioxide]] is called [[erbia]]. Erbium's properties are to a degree dictated by the kind and amount of impurities present. Erbium does not play any known biological role, but is thought to be able to stimulate [[metabolism]].<ref name="emsley">{{cite book | title = Nature's Building Blocks: An A-Z Guide to the Elements | last = Emsley | first = John | publisher = Oxford University Press | date = 2001 | location = Oxford, England, UK | isbn = 978-0-19-850340-8 | chapter = Erbium | pages = [https://archive.org/details/naturesbuildingb0000emsl/page/136 136–139] | chapter-url = https://books.google.com/books?id=j-Xu07p3cKwC | url = https://archive.org/details/naturesbuildingb0000emsl/page/136 }}</ref>

Erbium is [[Ferromagnetism|ferromagnetic]] below 19&nbsp;K, [[Antiferromagnetism|antiferromagnetic]] between 19 and 80 K and [[Paramagnetism|paramagnetic]] above 80&nbsp;K.<ref>{{cite journal| author = Jackson, M.| title = Magnetism of Rare Earth| url = http://www.irm.umn.edu/quarterly/irmq10-3.pdf| journal = The IRM Quarterly| volume = 10| issue = 3| page = 1| date = 2000| access-date = 2009-05-03| archive-url = https://web.archive.org/web/20170712151422/http://www.irm.umn.edu/quarterly/irmq10-3.pdf| archive-date = 2017-07-12| url-status = dead}}</ref>

Erbium can form propeller-shaped atomic clusters Er<sub>3</sub>N, where the distance between the erbium atoms is 0.35&nbsp;nm. Those clusters can be isolated by encapsulating them into [[fullerene]] molecules, as confirmed by [[transmission electron microscopy]].<ref>{{cite journal| title = Structures of ''D''<sub>5</sub>''<sub>d</sub>''-C<sub>80</sub> and ''I''<sub>h</sub>''-Er''<sub>3</sub>N@C<sub>80</sub> Fullerenes and Their Rotation Inside Carbon Nanotubes Demonstrated by Aberration-Corrected Electron Microscopy| date = 2007| journal = Nano Letters| volume = 7| page = 3704|bibcode = 2007NanoL...7.3704S| issue = 12 |doi =10.1021/nl0720152|last1 = Sato|first1 = Yuta| last2 = Suenaga| first2 = Kazu| last3 = Okubo| first3 = Shingo| last4 = Okazaki| first4 = Toshiya| last5 = Iijima| first5 = Sumio}}</ref>

Like most [[rare-earth elements]], erbium is usually found in the +3 oxidation state. However, it is possible for erbium to also be found in the 0, +1 and +2<ref>{{Cite journal |last1=MacDonald |first1=Matthew R. |last2=Bates |first2=Jefferson E. |last3=Fieser |first3=Megan E. |last4=Ziller |first4=Joseph W. |last5=Furche |first5=Filipp |last6=Evans |first6=William J. |date=2012-05-23 |title=Expanding Rare-Earth Oxidation State Chemistry to Molecular Complexes of Holmium(II) and Erbium(II) |url=https://pubs.acs.org/doi/10.1021/ja303357w |journal=Journal of the American Chemical Society |language=en |volume=134 |issue=20 |pages=8420–8423 |doi=10.1021/ja303357w |pmid=22583320 |bibcode=2012JAChS.134.8420M |issn=0002-7863}}</ref> oxidation states.