Editing Rhenium (section)

===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.