Editing Einsteinium (section)

==Chemical compounds==
{{Main|Einsteinium compounds}}
{|class = wikitable
|+Crystal structure and lattice constants of some Es compounds
!Compound!!Color !! Symmetry!![[Space group]]!!No!![[Pearson symbol]]||''a'' ([[picometre|pm]])!!''b'' (pm)!!''c'' (pm)
|-
|Es{{sub|2}}O{{sub|3}}|| Colorless||Cubic<ref name="ES2O3" />||Ia{{overline|3}}|| 206||cI80||1076.6|| ||
|-
|Es{{sub|2}}O{{sub|3}}|| Colorless||[[Monoclinic crystal system|Monoclinic]]<ref name="ox1" />||C2/m||12|| mS30||1411||359 || 880
|-
|Es{{sub|2}}O{{sub|3}}|| Colorless||Hexagonal<ref name="ox1" />|| P{{overline|3}}m1||164 ||hP5||370|| ||600
|-
|EsF{{sub|3}}|| ||Hexagonal<ref name="ES_F3" />|| || || || || ||
|-
|EsF{{sub|4}}|| ||Monoclinic<ref>{{cite journal|last1=Kleinschmidt|first1=P.|title=Thermochemistry of the actinides|journal=Journal of Alloys and Compounds|volume=213–214|pages=169–172|date=1994|doi=10.1016/0925-8388(94)90898-2|url=https://digital.library.unt.edu/ark:/67531/metadc1401691/|access-date=2019-07-14|archive-date=2020-03-16|archive-url=https://web.archive.org/web/20200316233629/https://digital.library.unt.edu/ark:/67531/metadc1401691/|url-status=live}}</ref> || C2/c||15 ||mS60 || || ||
|-
|EsCl{{sub|3}}||Orange||Hexagonal<ref>{{cite journal|last1=Fujita|first1=D.|title=Crystal structures and lattice parameters of einsteinium trichloride and einsteinium oxychloride|journal=Inorganic and Nuclear Chemistry Letters|volume=5|pages=307–313|date=1969|doi=10.1016/0020-1650(69)80203-5|issue=4|last2=Cunningham|first2=B. B.|last3=Parsons|first3=T. C.|url=http://www.escholarship.org/uc/item/7hz778j2|access-date=2019-07-14|archive-date=2020-03-13|archive-url=https://web.archive.org/web/20200313022142/https://escholarship.org/uc/item/7hz778j2|url-status=live}}</ref><ref name="m99" />|| C6{{sub|3}}/m|| ||hP8 ||727 || ||410
|-
|EsBr{{sub|3}}||Yellow||Monoclinic<ref>{{cite journal|last1=Fellows|first1=R.|title=X-ray diffraction and spectroscopic studies of crystalline einsteinium(III) bromide, {{sup|253}}EsBr{{sub|3}}|journal=Inorganic and Nuclear Chemistry Letters|volume=11|pages=737–742|date=1975|doi=10.1016/0020-1650(75)80090-0|issue=11|last2=Peterson|first2=J. R.|last3=Noé|first3=M.|last4=Young|first4=J. P.|last5=Haire|first5=R. G.}}</ref>||C2/m || 12|| mS16||727 ||1259 || 681
|-
|EsI{{sub|3}}||Amber||Hexagonal<ref name="h1595" /><ref name="s62">[[#Seaborg|Seaborg]], p. 62</ref>||R{{overline|3}} ||148 ||hR24 || 753|| ||2084
|-
|EsOCl|| ||Tetragonal<ref name="h1595">[[#Haire|Haire]], pp. 1595–1596</ref><ref name="YOUNG_1981" />|| P4/nmm|| || ||394.8 || || 670.2
|}

===Oxides===
Einsteinium(III) oxide (Es{{sub|2}}O{{sub|3}}) was obtained by burning einsteinium(III) nitrate. It forms colorless cubic crystals, which were first characterized from microgram samples sized about 30 nanometers.<ref name="g1268">[[#Greenwood|Greenwood]], p. 1268</ref><ref name="ES2O3">{{cite journal|last1=Haire|first1=R. G.|last2=Baybarz|first2=R. D.|title=Identification and analysis of einsteinium sesquioxide by electron diffraction|journal=Journal of Inorganic and Nuclear Chemistry|volume=35|pages=489–496|date=1973|doi=10.1016/0022-1902(73)80561-5|issue=2}}</ref> Two other phases, [[Monoclinic crystal system|monoclinic]] and hexagonal, are known for this oxide. The formation of a certain Es{{sub|2}}O{{sub|3}} phase depends on the preparation technique and sample history, and there is no clear phase diagram. Interconversions between the three phases can occur spontaneously, as a result of self-irradiation or self-heating.<ref name="h1598">[[#Haire|Haire]], p. 1598</ref> The hexagonal phase is isotypic with [[lanthanum oxide]] where the Es{{sup|3+}} ion is surrounded by a 6-coordinated group of O{{sup|2−}} ions.<ref name="ox1">{{cite book|title=Handbook on the Physics and Chemistry of Rare Earths|volume=18|chapter=Lanthanides and Actinides Chemistry|editor=K.A. Gscheidner, Jr. |display-editors=etal|location=North-Holland, New York|date=1994|pages=414–505|isbn=978-0-444-81724-2|author=Haire, R. G.|author2=Eyring, L.|name-list-style=amp}}</ref><ref name="h1595" />

===Halides===
[[File:Einsteinium triiodide by transmitted light.jpg|thumb|[[Einsteinium(III) iodide]] glowing in the dark]]

Einsteinium [[halide]]s are known for the oxidation states +2 and +3.<ref name="YOUNG_1981">{{cite journal|last1=Young|first1=J. P.|last2=Haire|first2=R. G.|last3=Peterson|first3=J. R.|last4=Ensor|first4=D. D.|last5=Fellow|first5=R. L.|title=Chemical consequences of radioactive decay. 2. Spectrophotometric study of the ingrowth of berkelium-249 and californium-249 into halides of einsteinium-253|journal=Inorganic Chemistry|volume=20|pages=3979–3983|date=1981|doi=10.1021/ic50225a076|issue=11}}</ref><ref name = "HOWI_1969">[[#Holleman|Holleman]], p. 1969</ref> The most stable state is +3 for all halides from fluoride to iodide.

Einsteinium(III) fluoride (EsF{{sub|3}}) can be precipitated from Es(III) chloride solutions upon reaction with [[fluoride]] ions. An alternative preparation procedure is to exposure Es(III) oxide to [[chlorine trifluoride]] (ClF{{sub|3}}) or F{{sub|2}} gas at a pressure of 1–2 atmospheres and temperature 300–400°C. The EsF{{sub|3}} crystal structure is hexagonal, as in californium(III) fluoride (CfF{{sub|3}}) where the Es{{sup|3+}} ions are 8-fold coordinated by fluorine ions in a bicapped [[Octahedral molecular geometry#Trigonal prismatic geometry|trigonal prism]] arrangement.<ref name="ES_F3">{{cite journal|last1=Ensor|first1=D. D.|last2=Peterson|first2=J. R.|last3=Haire|first3=R. G.|last4=Young|first4=J. P.|title=Absorption spectrophotometric study of {{sup|253}}EsF{{sub|3}} and its decay products in the bulk-phase solid state|journal=Journal of Inorganic and Nuclear Chemistry|volume=43|pages=2425–2427|date=1981|doi=10.1016/0022-1902(81)80274-6|issue=10}}</ref><ref name="g1270">[[#Greenwood|Greenwood]], p. 1270</ref><ref>{{cite journal|last1=Young|first1=J. P.|last2=Haire|first2=R. G.|last3=Fellows|first3=R. L.|last4=Peterson|first4=J. R.|title=Spectrophotometric studies of transcurium element halides and oxyhalides in the solid state|journal=Journal of Radioanalytical Chemistry|volume=43|pages=479–488|date=1978|doi=10.1007/BF02519508|issue=2|bibcode=1978JRNC...43..479Y |s2cid=95361392}}</ref>

Es(III) chloride (EsCl{{sub|3}}) can be prepared by annealing Es(III) oxide in the atmosphere of dry hydrogen chloride vapors at about 500°C for some 20 minutes. It crystallizes upon cooling at about 425°C into an orange solid with a [[hexagonal crystal family|hexagonal]] structure of [[uranium(III) chloride|UCl{{sub|3}} type]], where einsteinium atoms are 9-fold coordinated by chlorine atoms in a tricapped trigonal prism geometry.<ref name="m99">Miasoedov, B. F. Analytical chemistry of transplutonium elements, Wiley, 1974 (Original from the University of California), {{ISBN|0-470-62715-8}}, p. 99</ref><ref name="g1270" /><ref>{{cite journal|last1=Fujita|first1=D.|title=The solution absorption spectrum of Es<sup>3+</sup>|journal=Inorganic and Nuclear Chemistry Letters|volume=5|pages=245–250|date=1969|doi=10.1016/0020-1650(69)80192-3|issue=4|last2=Cunningham|first2=B. B.|last3=Parsons|first3=T. C.|last4=Peterson|first4=J. R.|url=http://www.escholarship.org/uc/item/3s43w87r|access-date=2019-07-14|archive-date=2020-03-09|archive-url=https://web.archive.org/web/20200309022304/https://escholarship.org/uc/item/3s43w87r|url-status=live}}</ref> [[Einsteinium(III) bromide]] (EsBr{{sub|3}}) is a pale-yellow solid with a [[monoclinic crystal system|monoclinic]] structure of [[aluminium chloride|AlCl{{sub|3}} type]], where the einsteinium atoms are [[Octahedral molecular geometry|octahedrally]] coordinated by bromine (coordination number 6).<ref name="s62" /><ref name="g1270" />

The divalent compounds of einsteinium are obtained by reducing the trivalent halides with [[hydrogen]]:<ref name="ES_II">{{cite journal|url=http://hal.archives-ouvertes.fr/docs/00/21/88/31/PDF/ajp-jphyscol197940C435.pdf|title=Preparation, characterization, and decay of einsteinium(II) in the solid state|journal=Le Journal de Physique|author=Peterson, J.R.|display-authors=etal|volume=40|issue=4|page=C4–111|date=1979|doi=10.1051/jphyscol:1979435|citeseerx=10.1.1.729.8671|s2cid=95575017 |access-date=2010-11-24|archive-date=2012-03-07|archive-url=https://web.archive.org/web/20120307233035/http://hal.archives-ouvertes.fr/docs/00/21/88/31/PDF/ajp-jphyscol197940C435.pdf|url-status=live}} [http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=6593662 manuscript draft] {{Webarchive|url=https://web.archive.org/web/20130513121141/http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=6593662 |date=2013-05-13 }}</ref>
:2 EsX{{sub|3}} + H{{sub|2}} → 2 EsX{{sub|2}} + 2 HX; X = F, Cl, Br, I

[[Einsteinium(II) chloride]] (EsCl{{sub|2}}),<ref>Fellows, R.L.; Young, J.P.; Haire, R.G. and Peterson J.R. (1977) in: GJ McCarthy and JJ Rhyne (eds) ''The Rare Earths in Modern Science and Technology'', Plenum Press, New York, pp. 493–499.</ref> [[einsteinium(II) bromide]] (EsBr{{sub|2}}),<ref>Young, J.P.; Haire R.G., Fellows, R.L.; Noe, M. and Peterson, J.R. (1976) "Spectroscopic and X-Ray Diffraction Studies of the Bromides of Californium-249 and Einsteinium-253", in: W. Müller and R. Lindner (eds.) ''Plutonium 1975'', North Holland, Amsterdam, pp. 227–234.</ref> and [[einsteinium(II) iodide]] (EsI{{sub|2}})<ref name = "YOUNG_1981" /> have been produced and characterized by optical absorption, with no structural information available yet.<ref name="s62" />

Known oxyhalides of einsteinium include EsOCl,<ref name="YOUNG_1981" /> EsOBr<ref name="ES_II" /> and EsOI.<ref name="YOUNG_1981" /> These salts are synthesized by treating a trihalide with a vapor mixture of water and the corresponding hydrogen halide: for example, EsCl{{sub|3}} + H{{sub|2}}O/HCl to obtain EsOCl.<ref name="s60">[[#Seaborg|Seaborg]], p. 60</ref>

===Organoeinsteinium compounds===
Einsteinium's high radioactivity has a potential use in [[radiation therapy]], and organometallic complexes have been synthesized in order to deliver einsteinium to an appropriate organ in the body. Experiments have been performed on injecting einsteinium [[citric acid|citrate]] (as well as fermium compounds) to dogs.<ref name="h1579" /> Einsteinium(III) was also incorporated into β-diketone [[Chelation|chelate]] complexes, since analogous complexes with lanthanides previously showed strongest UV-excited [[luminescence]] among metallorganic compounds. When preparing einsteinium complexes, the Es{{sup|3+}} ions were 1000 times diluted with Gd{{sup|3+}} ions. This allowed reducing the radiation damage so that the compounds did not disintegrate during the 20 minutes required for the measurements. The resulting luminescence from Es{{sup|3+}} was much too weak to be detected. This was explained by the unfavorable relative energies of the individual constituents of the compound that hindered efficient energy transfer from the chelate matrix to Es{{sup|3+}} ions. Similar conclusion was drawn for americium, berkelium and fermium.<ref>{{cite journal|last1=Nugent|first1=Leonard J.|last2=Burnett|first2=J. L.|last3=Baybarz|first3=R. D.|last4=Werner|first4=George Knoll|last5=Tanner|first5=S. P.|last6=Tarrant|first6=J. R.|last7=Keller|first7=O. L.|title=Intramolecular energy transfer and sensitized luminescence in actinide(III) .beta.-diketone chelates|journal=The Journal of Physical Chemistry|volume=73|pages=1540–1549|date=1969|doi=10.1021/j100725a060|issue=5}}</ref>

Luminescence of Es{{sup|3+}} ions was however observed in inorganic hydrochloric acid solutions as well as in organic solution with di(2-ethylhexyl)orthophosphoric acid. It shows a broad peak at about 1064 nanometers (half-width about 100&nbsp;nm) which can be resonantly excited by green light (ca. 495&nbsp;nm wavelength). The luminescence has a lifetime of several microseconds and the quantum yield below 0.1%. The relatively high, compared to lanthanides, non-radiative decay rates in Es{{sup|3+}} were associated with the stronger interaction of f-electrons with the inner Es{{sup|3+}} electrons.<ref>{{cite journal|last1=Beitz|first1=J.|last2=Wester|first2=D.|last3=Williams|first3=C.|title=5f state interaction with inner coordination sphere ligands: Es{{sup|3+}} ion fluorescence in aqueous and organic phases|journal=Journal of the Less Common Metals|volume=93|pages=331–338|date=1983|doi=10.1016/0022-5088(83)90178-9|issue=2}}</ref>