Editing Erbium (section)

===Halides===

[[Erbium(III) fluoride]] is a pinkish powder<ref>{{Cite web|url=https://www.americanelements.com/erbium-fluoride-13760-83-3|title = Erbium Fluoride}}</ref> that can be produced by reacting [[erbium(III) nitrate]] and [[ammonium fluoride]].<ref>{{cite journal|journal=Journal of Materials Chemistry C|volume=2|issue=15|language=en|issn=2050-7526|date=2014|pages=2765|doi=10.1039/c3tc32540g|url=http://xlink.rsc.org/?DOI=c3tc32540g|title=Facile synthesis and enhancement upconversion luminescence of ErF3 nano/microstructures via Li+ doping|accessdate=2019-03-26|author=Linna Guo, Yuhua Wang, Zehua Zou, Bing Wang, Xiaoxia Guo, Lili Han, Wei Zeng|url-access=subscription}}</ref> It can be used to make infrared light-transmitting materials<ref>{{Cite journal |last1=Su |first1=W. T. |last2=Li |first2=B. |last3=Yin |first3=L. |last4=Yang |first4=L. |last5=Liu |first5=D. Q. |last6=Zhang |first6=F. S. |date=2007-05-15 |title=Crystallization and surface morphology evolution of erbium fluoride films on different substrates |url=https://linkinghub.elsevier.com/retrieve/pii/S0169433207001523 |journal=Applied Surface Science |volume=253 |issue=14 |pages=6259–6263 |doi=10.1016/j.apsusc.2007.01.087 |bibcode=2007ApSS..253.6259S |issn=0169-4332|url-access=subscription }}</ref> and up-converting luminescent materials,<ref>{{cite journal|journal=RSC Advances|volume=8|issue=22|language=en|issn=2046-2069|date=2018|pages=12165–12172|doi=10.1039/C8RA01245H|title=Understanding differences in Er 3+ –Yb 3+ codoped glass and glass ceramic based on upconversion luminescence for optical thermometry|author=Yingxin Hao, Shichao Lv, Zhijun Ma, Jianrong Qiu|pmid=35539388|pmc=9079277|bibcode=2018RSCAd...812165H|doi-access=free}}</ref> and is an intermediate in the production of erbium metal prior to its reduction with calcium.<ref name=":0" /> [[Erbium(III) chloride]] is a violet compounds that can be formed by first heating erbium(III) oxide and [[ammonium chloride]] to produce the [[ammonium]] salt of the pentachloride ([NH<sub>4</sub>]<sub>2</sub>ErCl<sub>5</sub>) then heating it in a vacuum at 350-400&nbsp;°C.<ref name=Brauer>{{cite book|title=Handbook of Preparative Inorganic Chemistry|edition=2nd|editor=Brauer, G. |publisher=Academic Press|year=1963|place=New York}}</ref><ref name=IS>{{cite book | last =Meyer | first =G. | title =The Ammonium Chloride Route to Anhydrous Rare Earth Chlorides-The Example of YCl<sub>3</sub> | chapter =The Ammonium Chloride Route to Anhydrous Rare Earth Chlorides—The Example of Ycl <sub>3</sub> | series =Inorganic Syntheses | volume =25 | year =1989 | pages =146–150 | doi =10.1002/9780470132562.ch35 | isbn =978-0-470-13256-2}}
</ref><ref name="EdelmannPoremba1997">{{cite book |title=Synthetic Methods of Organometallic and Inorganic Chemistry |volume=VI |last=Edelmann |first=F. T. |author2=Poremba, P. |editor=Herrmann, W. A. |year=1997 |publisher=Georg Thieme Verlag |location=Stuttgart |isbn=978-3-13-103021-4 }}</ref> It forms crystals of the [[aluminium chloride|{{chem2|AlCl3}}]] type, with [[monoclinic]] crystals and the [[point group]] ''C''2/m.<ref name="Tempelton">{{cite journal |vauthors=Tempelton DH, Carter GF | title= The Crystal Structure of Yttrium Trichloride and Similar Compounds | journal=J Phys Chem | year=1954 | pages=940–943 | doi= 10.1021/j150521a002 | volume= 58 | issue=11 }}</ref> Erbium(III) chloride hexahydrate also forms monoclinic crystals with the point group of ''P''2/''n'' (''P''2/''c'') - ''C''<sup>4</sup><sub>2h</sub>. In this compound, erbium is octa-coordinated to form {{chem2|[Er(H2O)6Cl2]+}} ions with the isolated {{chem2|Cl−}} completing the structure.<ref>{{cite journal |vauthors=Graebner EJ, Conrad GH, Duliere SF | title=Crystallographic data for solvated rare earth chlorides| journal=[[Acta Crystallographica]] | year=1966 | pages=1012–1013 | volume=21 | issue=6| doi=10.1107/S0365110X66004420 | bibcode=1966AcCry..21.1012G}}</ref>

[[Erbium(III) bromide]] is a violet solid. It is used, like other metal bromide compounds, in water treatment, chemical analysis and for certain crystal growth applications.<ref>{{Cite web|last=Elements|first=American|title=Erbium Bromide|url=https://www.americanelements.com/erbr.html|access-date=2020-11-16|website=American Elements|language=en}}</ref> [[Erbium(III) iodide]]<ref name="Taylor & Francis - Handbook of Inorganic Compounds, 2011 - p 163">{{cite book|last=Perry|first=Dale L|title=Handbook of Inorganic Compounds|publisher=[[Taylor & Francis]]|date=2011|edition=2|pages=163|isbn=9781439814628|url=https://books.google.com/books?id=SFD30BvPBhoC&q=%22Erbium+Boride%22&pg=PA163|accessdate=14 December 2013}}</ref> is a slightly pink compound that is insoluble in water. It can be prepared by directly reacting erbium with [[iodine]].<ref>{{Cite web|last=Elements|first=American|title=Erbium Iodide|url=https://www.americanelements.com/erbium-iodide-13813-42-8|access-date=2020-11-16|website=American Elements|language=en}}</ref>