Editing Rhenium (section)

==Characteristics==
Rhenium is a silvery-white metal with one of the highest [[melting point]]s of all elements, exceeded by only [[tungsten]]. (At standard pressure [[carbon]] sublimes rather than melts, though its sublimation point is comparable to the melting points of tungsten and rhenium.) It also has one of the highest [[boiling points]] of all elements, and the highest among stable elements. It is also one of the densest, exceeded only by [[platinum]], [[iridium]] and [[osmium]]. Rhenium has a hexagonal close-packed crystal structure.

Its usual commercial form is a powder, but this element can be consolidated by pressing and [[sintering]] in a vacuum or [[hydrogen]] atmosphere. This procedure yields a compact solid having a density above 90% of the density of the metal. When [[Annealing (metallurgy)|annealed]] this metal is very ductile and can be bent, coiled, or rolled.<ref name="CRC">{{cite book| first=C. R.| last=Hammond| chapter=The Elements| title=Handbook of Chemistry and Physics| edition=81st| publisher=CRC press| isbn=978-0-8493-0485-9| date=2004| chapter-url-access=registration| chapter-url=https://archive.org/details/crchandbookofche81lide}}</ref> Rhenium-molybdenum [[alloy]]s are [[Superconductivity|superconductive]] at 10 [[Kelvin|K]]; tungsten-rhenium alloys are also superconductive<ref>{{cite journal|title=Superconductivity of Some Alloys of the Tungsten-rhenium-carbon System|journal=Soviet Physics JETP|volume=27|page=13|date=1968|bibcode=1968JETP...27...13N|last=Neshpor|first=V. S.|author2=Novikov, V. I.|author3=Noskin, V. A.|author4=Shalyt, S. S.}}</ref> around 4–8 K, depending on the alloy. Rhenium metal superconducts at {{val|1.697|0.006|u=K}}.<ref>{{cite book | editor= Haynes, William M. | date = 2011 | title = CRC Handbook of Chemistry and Physics | edition = 92nd|page=12.60 | publisher = [[CRC Press]] | isbn = 978-1439855119| title-link = CRC Handbook of Chemistry and Physics }}</ref><ref>{{cite web|url=http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0622881 |archive-url=https://web.archive.org/web/20170206104641/http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0622881 |url-status=dead |archive-date=2017-02-06 |title=The Properties of Superconducting Mo-Re Alloys |author=Daunt, J. G. |author2=Lerner, E. |publisher=[[Defense Technical Information Center]] }}</ref>

In bulk form and at room temperature and atmospheric pressure, the element resists alkalis, [[sulfuric acid]], [[hydrochloric acid]], [[nitric acid]], and [[aqua regia]]. It will however, react with nitric acid upon heating.<ref>{{cite web | url=https://www.youtube.com/watch?v=Duk20wEVgJQ | title=Rhenium - A METAL WITHOUT WHICH THERE WOULdn't BE GASOLINE! | website=[[YouTube]] | date=July 2018 }}</ref>

===Isotopes===
{{Main|Isotopes of rhenium}}
Rhenium has one [[Stable nuclide|stable]] isotope, rhenium-185, which nevertheless occurs in minority abundance, a situation found only in two other elements ([[indium]] and [[tellurium]]). Naturally occurring rhenium is only 37.4% <sup>185</sup>Re, and 62.6% <sup>187</sup>Re, which is [[Radionuclide|unstable]] but has a very long [[half-life]] (~10<sup>10</sup> years). A kilogram of natural rhenium emits 1.07&nbsp;[[Becquerel|MBq]] of radiation due to the presence of this isotope. This lifetime can be greatly affected by the charge state of the rhenium atom.<ref>{{cite web|work=math.ucr.edu|url=http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/decay_rates.html|title=How to Change Nuclear Decay Rates|date=1993|first=Bill|last=Johnson|access-date=2009-02-21}}</ref><ref name="Bosch1996">{{cite journal|last1=Bosch|first1=F.|last2=Faestermann|first2=T.|last3=Friese|first3=J.|last4=Heine|first4=F.|last5=Kienle|first5=P.|last6=Wefers|first6=E.|last7=Zeitelhack|first7=K.|last8=Beckert|first8=K.|last9=Franzke|first9=B.|last10=Klepper|first10=O.|last11=Kozhuharov|first11=C.|last12=Menzel|first12=G.|last13=Moshammer|first13=R.|last14=Nolden|first14=F.|last15=Reich|first15=H.|last16=Schlitt|first16=B.|last17=Steck|first17=M.|last18=Stöhlker|first18=T.|last19=Winkler|first19=T.|last20=Takahashi|first20=K.|display-authors=3|title=Observation of bound-state ''β''<sup>−</sup> decay of fully ionized <sup>187</sup>Re: <sup>187</sup>Re-<sup>187</sup>Os Cosmochronometry|date=1996|journal=[[Physical Review Letters]]|volume=77|issue=26|pages=5190–5193|doi=10.1103/PhysRevLett.77.5190|bibcode=1996PhRvL..77.5190B|pmid=10062738}}</ref> The [[beta decay]] of <sup>187</sup>Re is used for [[rhenium–osmium dating]] of ores. The available energy for this beta decay (2.6&nbsp;[[keV]]) is the second lowest known among all [[radionuclide]]s, only behind the decay from <sup>115</sup>In to excited <sup>115</sup>Sn* (0.147&nbsp;keV).<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. | title=Experimental searches for rare alpha and beta decays | journal=The European Physical Journal A | publisher=Springer Science and Business Media LLC | volume=55 | issue=8 | year=2019 | page=140 | issn=1434-6001 | doi=10.1140/epja/i2019-12823-2| arxiv=1908.11458 | bibcode=2019EPJA...55..140B }}</ref> The isotope rhenium-186m is notable as being one of the longest lived [[metastable isotope]]s with a half-life of around 200,000 years. There are 33 other unstable isotopes that have been recognized, ranging from <sup>160</sup>Re to <sup>194</sup>Re, the longest-lived of which is <sup>183</sup>Re with a half-life of 70 days.{{NUBASE2016|ref}}

===Compounds===
{{main|Rhenium compounds}}

Rhenium compounds are known for all the [[oxidation states]] between −3 and +7 except −2. The oxidation states +7, +4, and +3 are the most common.<ref>{{cite book |last1=Housecroft |first1=Catherine E. |last2=Sharpe |first2=Alan G. |title=Inorganic Chemistry |date=2018|publisher=Pearson Prentice-Hal |isbn=978-1292-13414-7 |page=829 |edition=5th}}</ref> Rhenium is most available commercially as salts of [[perrhenate]], including [[sodium perrhenate|sodium]] and [[ammonium perrhenate]]s. These are white, water-soluble compounds.<ref name="Brauer">Glemser, O. (1963) "Ammonium Perrhenate" in ''Handbook of Preparative Inorganic Chemistry'', 2nd ed., G. Brauer (ed.), Academic Press, NY., Vol. 1, pp. 1476–85.</ref> Tetrathioperrhenate anion [ReS<sub>4</sub>]<sup>−</sup>  is possible.<ref>{{cite book |last1= Goodman |first1= JT |last2= Rauchfuss |first2= TB |chapter= Useful Reagents and Ligands | title = Inorganic Syntheses | series = [[Inorganic Syntheses]] | year = 2002 | volume = 33 | pages = 107–110 | doi=10.1002/0471224502.ch2| isbn = 0471208256 }}</ref>

====Halides and oxyhalides====
The most common rhenium chlorides are ReCl<sub>6</sub>, [[Rhenium pentachloride|ReCl<sub>5</sub>]], ReCl<sub>4</sub>, and [[Rhenium trichloride|ReCl<sub>3</sub>]].<ref name="G&W">{{Greenwood&Earnshaw2nd}}</ref> The structures of these compounds often feature extensive Re-Re bonding, which is characteristic of this metal in oxidation states lower than VII. Salts of [Re<sub>2</sub>Cl<sub>8</sub>]<sup>2−</sup> feature a [[quadruple bond|quadruple]] metal-metal bond. Although the highest rhenium chloride features Re(VI), fluorine gives the d<sup>0</sup> Re(VII) derivative [[rhenium heptafluoride]]. Bromides and iodides of rhenium are also well known, including [[rhenium pentabromide]] and [[rhenium tetraiodide]].

Like tungsten and molybdenum, with which it shares chemical similarities, rhenium forms a variety of [[Oxohalide|oxyhalides]]. The oxychlorides are most common, and include ReOCl<sub>4</sub>, ReOCl<sub>3</sub>.

====Oxides and sulfides====
[[File:Perrhenic-acid-3D-balls.png|left|thumb|upright=0.5|Perrhenic acid (H<sub>4</sub>Re<sub>2</sub>O<sub>9</sub>) adopts an unconventional structure.]]

The most common oxide is the volatile yellow [[rhenium(VII) oxide|Re<sub>2</sub>O<sub>7</sub>]]. The red [[ReO3|rhenium trioxide]] ReO<sub>3</sub> adopts a [[perovskite]]-like structure. Other oxides include Re<sub>2</sub>O<sub>5</sub>, [[Rhenium(IV) oxide|ReO<sub>2</sub>]], and Re<sub>2</sub>O<sub>3</sub>.<ref name="G&W" /> The [[sulfide]]s are [[rhenium disulfide|ReS<sub>2</sub>]] and [[Rhenium(VII) sulfide|Re<sub>2</sub>S<sub>7</sub>]]. Perrhenate salts can be converted to tetrathioperrhenate by the action of [[ammonium hydrosulfide]].<ref>{{cite book|last =Goodman|first=J. T.|author2=Rauchfuss, T. B. |chapter=Useful Reagents and Ligands |title=Inorganic Syntheses|date=2002|volume=33|pages=107–110|doi=10.1002/0471224502.ch2|isbn=9780471208259}}</ref>

====Other compounds====
[[Rhenium diboride]] (ReB<sub>2</sub>) is a hard compound having a hardness similar to that of [[tungsten carbide]], [[silicon carbide]], [[titanium diboride]] or [[zirconium diboride]].<ref>{{cite journal| first=Jiaqian|last=Qin|author2=He, Duanwei |author3=Wang, Jianghua |author4=Fang, Leiming |author5=Lei, Li |author6=Li, Yongjun |author7=Hu, Juan |author8=Kou, Zili |author9= Bi, Yan |title=Is Rhenium Diboride a Superhard Material?| journal= Advanced Materials |volume=20|date =2008| pages=4780–4783| doi=10.1002/adma.200801471| issue=24|bibcode=2008AdM....20.4780Q |s2cid=98327405 }}</ref>

====Organorhenium compounds====
{{Main|Organorhenium chemistry}}
[[Dirhenium decacarbonyl]] is the most common entry to organorhenium chemistry. Its reduction with sodium [[Amalgam (chemistry)|amalgam]] gives Na[Re(CO)<sub>5</sub>] with rhenium in the formal oxidation state −1.<ref>{{cite journal|doi = 10.1002/cber.19901230103|title = Nucleophile Addition von Carbonylmetallaten an kationische Alkin-Komplexe [CpL2M(η2-RC≡CR)]+ (M = Ru, Fe): μ-η1:η1-Alkin-verbrückte Komplexe|date = 1990|author = Breimair, Josef|journal = Chemische Berichte|volume = 123|page = 7|last2 = Steimann|first2 = Manfred|last3 = Wagner|first3 = Barbara|last4 = Beck|first4 = Wolfgang}}</ref> Dirhenium decacarbonyl can be oxidised with [[bromine]] to [[bromopentacarbonylrhenium(I)]]:<ref>{{cite book|title=Inorganic Syntheses|first=Steven P.|last =Schmidt|author2=Trogler, William C. |author3=Basolo, Fred |chapter=Pentacarbonylrhenium Halides | volume=28|date=1990|pages=154–159|doi=10.1002/9780470132593.ch42|isbn=978-0-470-13259-3}}</ref>
:Re<sub>2</sub>(CO)<sub>10</sub> + Br<sub>2</sub> → 2 Re(CO)<sub>5</sub>Br

Reduction of this pentacarbonyl with [[zinc]] and [[acetic acid]] gives [[pentacarbonylhydridorhenium]]:<ref name="Urb">{{cite book|author=Michael A. Urbancic|author2=John R. Shapley|chapter=Pentacarbonylhydridorhenium |title=Inorganic Syntheses|volume=28|pages=165–168|date=1990|doi =10.1002/9780470132593.ch43|isbn=978-0-470-13259-3}}</ref>
:Re(CO)<sub>5</sub>Br + Zn + HOAc → Re(CO)<sub>5</sub>H + ZnBr(OAc)

[[Methylrhenium trioxide]] ("MTO"), CH<sub>3</sub>ReO<sub>3</sub> is a volatile, colourless solid that has been used as a [[catalyst]] in some laboratory experiments. It can be prepared by many routes, a typical method is the reaction of Re<sub>2</sub>O<sub>7</sub> and [[tetramethyltin]]:
:Re<sub>2</sub>O<sub>7</sub> + (CH<sub>3</sub>)<sub>4</sub>Sn → CH<sub>3</sub>ReO<sub>3</sub> + (CH<sub>3</sub>)<sub>3</sub>SnOReO<sub>3</sub>
Analogous alkyl and aryl derivatives are known. MTO catalyses for the oxidations with [[hydrogen peroxide]]. Terminal [[alkyne]]s yield the corresponding acid or ester, internal alkynes yield diketones, and [[alkene]]s give epoxides. MTO also catalyses the conversion of [[aldehyde]]s and [[diazoalkane]]s into an alkene.<ref>Hudson, A. (2002) “Methyltrioxorhenium” in ''Encyclopedia of Reagents for Organic Synthesis''. John Wiley & Sons: New York, {{ISBN|9780470842898}}, {{doi|10.1002/047084289X}}.</ref>

====Nonahydridorhenate====
[[File:Nonahydridorhenate-3D-balls.png|right|thumb|upright=0.5|Structure of {{chem|ReH|9|2-}}.]]
A distinctive derivative of rhenium is [[Potassium nonahydridorhenate|nonahydridorhenate]], originally thought to be the ''rhenide'' anion, Re<sup>−</sup>, but actually containing the {{chem|ReH|9|2-}} anion in which the oxidation state of rhenium is +7.

===Occurrence===
[[Image:Molybdenit 1.jpg|thumb|left|Molybdenite]]
Rhenium is one of the rarest elements in [[Earth's crust]] with an average concentration of 1&nbsp;ppb;<ref name="G&W" /> other sources quote the number of 0.5&nbsp;ppb making it the 77th most abundant element in Earth's crust.<ref name="Emsley2001p358">{{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=Rhenium|pages=[https://archive.org/details/naturesbuildingb0000emsl/page/358 358–360]|chapter-url=https://books.google.com/books?id=j-Xu07p3cKwC|url=https://archive.org/details/naturesbuildingb0000emsl/page/358}}</ref> Rhenium is probably not found free in nature (its possible natural occurrence is uncertain), but occurs in amounts up to 0.2%<ref name="G&W" /> in the mineral [[molybdenite]] (which is primarily [[molybdenum disulfide]]), the major commercial source, although single molybdenite samples with up to 1.88% have been found.<ref name="Rousch" /> [[Chile]] has the world's largest rhenium reserves, part of the copper ore deposits, and was the leading producer as of 2005.<ref>{{cite web|url=http://minerals.usgs.gov/minerals/pubs/country/2005/cimyb05.pdf |first=Steve T.|last=Anderson| publisher=[[United States Geological Survey]]|title=2005 Minerals Yearbook: Chile|access-date=2008-10-26}}</ref> It was only recently (in 1994) that the first rhenium [[mineral]] was found and described, a rhenium [[sulfide mineral]] (ReS<sub>2</sub>) condensing from a [[fumarole]] on [[Kudriavy]] volcano, [[Iturup]] island, in the [[Kuril Islands]].<ref>{{cite journal|last=Korzhinsky|first=M. A.|author2=Tkachenko, S. I. |author3=Shmulovich, K. I. |author4=Taran Y. A. |author5= Steinberg, G. S. | date=2004-05-05|title=Discovery of a pure rhenium mineral at Kudriavy volcano|journal=[[Nature (journal)|Nature]]|volume=369|pages=51–52|doi=10.1038/369051a0|issue=6475|bibcode = 1994Natur.369...51K |s2cid=4344624}}</ref> Kudriavy discharges up to 20–60&nbsp;kg rhenium per year mostly in the form of rhenium disulfide.<ref>{{cite journal| last1 = Kremenetsky| first1 = A. A.| last2 = Chaplygin| first2 = I. V.| title = Concentration of rhenium and other rare metals in gases of the Kudryavy Volcano (Iturup Island, Kurile Islands)| journal = Doklady Earth Sciences| volume = 430| issue = 1| page = 114| date = 2010| doi = 10.1134/S1028334X10010253|bibcode = 2010DokES.430..114K | s2cid = 140632604}}</ref><ref>{{cite journal | last1 = Tessalina | first1 = S. | last2 = Yudovskaya | first2 = M. | last3 = Chaplygin | first3 = I. | last4 = Birck | first4 = J. | last5 = Capmas | first5 = F. | title = Sources of unique rhenium enrichment in fumaroles and sulphides at Kudryavy volcano | journal = Geochimica et Cosmochimica Acta | volume = 72 | page = 889 | date = 2008 | doi = 10.1016/j.gca.2007.11.015 | bibcode=2008GeCoA..72..889T | issue = 3}}</ref> Named [[rheniite]], this rare mineral commands high prices among collectors.<ref>{{cite web|url=http://www.galleries.com/minerals/sulfides/rheniite/rheniite.htm|publisher=Amethyst Galleries|title=The Mineral Rheniite}}</ref> <!--Dr. Kremenetsky from [[Russian Academy of Sciences|RAS]] Mineralogy Institute argues that this source could be commercially exploited,<ref>[http://www.nkj.ru/archive/articles/5340/ Завод на вулкане] // Наука и жизнь, № 11, 2000, in Russian.</ref> but currently there is no active attempts to extract it.-->
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