Rhenium
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225686497
2008-07-14T22:11:08Z
Arkuat
29003
/* Characteristics */ section title according to wikiproject elements
{{Elementbox_header | number=75 | symbol=Re | name=rhenium | left=[[tungsten]] | right=[[osmium]] | above=[[technetium|Tc]] | below=[[bohrium|Bh]] | color1=#ffc0c0 | color2=black }}
{{Elementbox_series | [[transition metal]]s }}
{{Elementbox_groupperiodblock | group=7 | period=6 | block=d }}
{{Elementbox_appearance_img | Re,75| grayish white }}
{{Elementbox_atomicmass_gpm | [[1 E-25 kg|186.207]][[List of elements by atomic mass|(1)]] }}
{{Elementbox_econfig | [[[xenon|Xe]]] 4f<sup>14</sup> 5d<sup>5</sup> 6s<sup>2</sup> }}
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{{Elementbox_phase | [[solid]] }}
{{Elementbox_density_gpcm3nrt | 21.02 }}
{{Elementbox_densityliq_gpcm3mp | 18.9 }}
{{Elementbox_meltingpoint | k=3459 | c=3186 | f=5767 }}
{{Elementbox_boilingpoint | k=5869 | c=5596 | f=10105 }}
{{Elementbox_heatfusion_kjpmol | 60.43 }}
{{Elementbox_heatvaporiz_kjpmol | 704 }}
{{Elementbox_heatcapacity_jpmolkat25 | 25.48 }}
{{Elementbox_vaporpressure_katpa | 3303 | 3614 | 4009 | 4500 | 5127 | 5954 | comment= }}
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{{Elementbox_crystalstruct | hexagonal }}
{{Elementbox_oxistates | '''7''', '''6''', 5, 4, 3, 2, 1, −1, −2, −3<br/>(mildly [[acid]]ic oxide) }}
{{Elementbox_electroneg_pauling | 1.9 }}
{{Elementbox_ionizationenergies4 | 760 | 1260 | 2510 }}
{{Elementbox_atomicradius_pm | [[1 E-10 m|135]] }}
{{Elementbox_atomicradiuscalc_pm | [[1 E-10 m|188]] }}
{{Elementbox_covalentradius_pm | [[1 E-10 m|159]] }}
{{Elementbox_section_miscellaneous | color1=#ffc0c0 | color2=black }}
{{Elementbox_magnetic | ? }}
{{Elementbox_eresist_ohmmat20 | 193 n}}
{{Elementbox_thermalcond_wpmkat300k | 48.0 }}
{{Elementbox_thermalexpansion_umpmkat25 | 6.2 }}
{{Elementbox_speedofsound_rodmpsat20 | 4700 }}
{{Elementbox_youngsmodulus_gpa | 463 }}
{{Elementbox_shearmodulus_gpa | 178 }}
{{Elementbox_bulkmodulus_gpa | 370 }}
{{Elementbox_poissonratio | 0.30 }}
{{Elementbox_mohshardness | 7.0 }}
{{Elementbox_vickershardness_mpa | 2450 }}
{{Elementbox_brinellhardness_mpa | 1320 }}
{{Elementbox_cas_number | 7440-15-5 }}
{{Elementbox_isotopes_begin | color1=#ffc0c0 | color2=black }}
{{Elementbox_isotopes_stable | mn=185 | sym=Re | na=37.4% | n=110 }}
{{Elementbox_isotopes_decay2 | mn=187 | sym=Re
| na=62.6% | hl=4.35×10<sup>10</sup> y
| dm1=[[alpha decay|α]] (not observed) | de1=1.653 | pn1=183 | ps1=[[tantalum|Ta]]
| dm2=[[beta decay|β<sup>-</sup>]] | de2=0.0026 | pn2=187 | ps2=[[osmium|Os]] }}
{{Elementbox_isotopes_end}}
{{Elementbox_footer | color1=#ffc0c0 | color2=black }}
'''Rhenium''' ({{pronEng|ˈriːniəm}}) is a [[chemical element]] with the symbol '''Re''' and [[atomic number]] 75. A rare silvery-white, heavy, [[polyvalent]] [[transition metal]], rhenium resembles [[manganese]] chemically, and is used in some [[alloy]]s. Rhenium is obtained as a [[by-product]] of [[molybdenum]] refinement, and rhenium-molybdenum alloys are [[superconductivity|superconducting]].<ref>{{cite web | url = http://stinet.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0622881 | title = The Properties of Superconducting Mo-Re Alloys | author = Daunt, J. G.; Lerner, E.| publisher = [[Defense Technical Information Center]]}}</ref> It was the last naturally occurring stable element to be discovered<ref name = usgs>{{cite web | publisher = [[United States Geological Survey]] | url = http://minerals.usgs.gov/minerals/pubs/commodity/rhenium/ | work = Minerals Information | title = Rhenium: Statistics and Information | date = 2008 | accessdate = 2008-02-03}}</ref> and is among the ten most expensive metals on Earth, at times exceeding US$ 11,000 per [[kilogram]]).<ref name="BBC">British Rhenium merchant Anthony Hipman, speaking on BBC News broadcast, June 18, 2008</ref> About 35 kilograms of Rhenium are required in the construction of a commercial jet engine.<ref name = "BBC"/>
== Characteristics ==
Rhenium is a silvery white metal, lustrous, and has one of the highest [[melting point]]s of all elements, exceeded by only [[tungsten]] and [[carbon]]. It is also one of the most dense, exceeded only by [[platinum]], [[iridium]] and [[osmium]]. Rhenium has the widest range of [[oxidation state]]s of any known element: -3, -1, 0, +1, +2, +3, +4, +5, +6 and +7. The oxidation states +7, +6, +4, +2 and -1 are the most common.
Its usual commercial form is a powder, but this element can be consolidated by pressing and resistance-sintering in a vacuum or [[hydrogen]] atmosphere. This procedure yields a compact shape that is in excess of 90 percent of the density of the metal. When [[Annealing (metallurgy)|annealed]] this metal is very ductile and can be bent, coiled, or rolled. Rhenium-molybdenum [[alloy]]s are superconductive at 10 [[Kelvin|K]]; tungsten-rhenium [[alloy]]s are also superconductive,<ref>{{cite journal | title = Superconductivity of Some Alloys of the Tungsten-rhenium-carbon System | journal = [[Soviet Physics JETP]] | volume = 27 | pages = 13 | date = 1968 | bibcode = 1968JETP...27...13N | author = Neshpor, V. S.; Novikov, V. I.; Noskin, V. A.; Shalyt, S. S.}}</ref> around 4-8 [[Kelvin|K]] depending on the alloy. Rhenium metal superconducts at 2.4 [[Kelvin|K]].<ref>{{cite journal | author = J. G. Daunt and T. S. Smith | title = Superconductivity of Rhenium | year = 1952 | journal = [[Physical Review]] | volume = 88 | issue = 2 | pages = 309 | doi = 10.1103/PhysRev.88.309}}</ref>
== Applications ==
This element is used in [[platinum]]-rhenium [[catalyst]]s which in turn are primarily used in making [[lead]]-free, high-octane [[gasoline]] and in high-temperature superalloys that are used to make [[jet engine]] parts.<ref name="USGS_2008_summary">{{cite web | title = Rhenium | work = Mineral Commodity Summaries | publisher = U.S. Geological Survey | date = January 2008 | url = http://minerals.usgs.gov/minerals/pubs/commodity/rhenium/mcs-2008-rheni.pdf | format = PDF | accessdate = 2008-02-17}}</ref> Other uses:
* Widely used as filaments in [[mass spectrograph]]s and in [[ion gauge]]s.
* An additive to tungsten and [[molybdenum]]-based alloys to increase ductility in these alloys.
* An additive to tungsten in some [[x-ray]] sources.
* Rhenium [[catalyst]]s are very resistant to [[catalyst poisoning|chemical poisoning]], and so are used in certain kinds of hydrogenation reactions.
* [[Switch#Contacts|Electrical contact]] material due to its good [[Wear|wear resistance]] and ability to withstand arc corrosion.
* [[Thermocouple]]s containing alloys of rhenium and tungsten are used to measure temperatures up to 2200 °[[Celsius|C]].
* Rhenium wire is used in photoflash lamps in [[photography]].
* Rhenium forms [[rhenium diboride]] with [[boron]]. It is a compound noted for its extreme hardness.<ref name="New Scientist">{{cite news | author = Inman, M. | date = 20 April 2007 | url = http://www.newscientisttech.com/article.ns?id=dn11670&feedId=online-news_rss20 | title = Super-tough material mimics metal and crystal | publisher = New Scientist Tech}}</ref><ref>{{cite journal | author = H.-Y. Chung, M. B. Weinberger, J. B. Levine, A. Kavner, J.-M. Yang, S. H. Tolbert and R. B. Kaner | title = Synthesis of Ultra-Incompressible Superhard Rhenium Diboride at Ambient Pressure | year = 2007 | journal = [[Science (journal)|Science]] | volume = 316 | issue = 5823 | pages = 436–439 | doi = 10.1126/science.1139322 | pmid = 17446399}}</ref>
* Isotopes of rhenium are radioactive. The 188 isotope, with a half-life of 69 days, has been tested for treatment of [[liver cancer]]. The 188 isotope may be obtained in the form of a generator.<ref>{{cite web | publisher = [[Oak Ridge National Laboratory]] | title = The Tungsten-188 and Rhenium-188 Generator Information | date = 2005 | url = http://www.ornl.gov/sci/nuclear_science_technology/nu_med/188info.htm | accessdate = 2008-02-03}}</ref>
* Related by [[periodic trends]], rhenium has a similar chemistry with [[technetium]]; work done to label rhenium onto target compounds can often be translated to technetium. This is useful for radiopharmacy, where it is difficult to work with technetium - especially the 99m isotope used in medicine - due to its expense and short half-life.
== History ==
Rhenium ([[Latin]] ''Rhenus'' meaning "[[Rhine]]") was the next-to-last naturally occurring element to be discovered and the last element to be discovered having a stable isotope. The existence of a yet undiscovered element at this position in the [[periodic table]] had been predicted by [[Henry Moseley]] in [[1914]]. It is generally considered to have been discovered by [[Walter Noddack]], [[Ida Tacke]], and [[Otto Berg]] in [[Germany]]. In [[1925]] they reported that they detected the element in [[platinum]] ore and in the mineral [[columbite]]. They also found rhenium in [[gadolinite]] and [[molybdenite]]. In 1928 they were able to extract 1 g of the element by processing 660 [[kilogram|kg]] of molybdenite.
The process was so complicated and the cost so high that production was discontinued until early [[1950]] when tungsten-rhenium and molybdenum-rhenium alloys were prepared. These alloys found important applications in industry that resulted in a great demand for the rhenium produced from the molybdenite fraction of porphyry [[copper]] ores.
In [[1908]], [[Japan]]ese chemist [[Masataka Ogawa]] announced that he discovered the 43rd element, and named it ''nipponium'' (Np) after [[Japan]] (which is ''Nippon'' in Japanese). However, later analysis indicated the presence of rhenium (element 75), not [[Technetium|element 43]]. The symbol Np was later used for the element [[neptunium]].
== Occurrence ==
Rhenium is not found free in nature, but occurs in amounts up to 0.2% in the mineral [[molybdenite]], the major commercial source. It was only recently that the first rhenium [[mineral]] was found and described (in 1994), a rhenium [[sulfide mineral]] (ReS<sub>2</sub>) condensing from a [[fumarole]] on [[Russia]]'s [[Kudriavy]] volcano, in the [[Kurile Islands]].<ref>{{cite journal
| last = Korzhinsky | first = M.A.
| coauthors = S. I. Tkachenko, K. I. Shmulovich, Y. A. Taran & G. S. Steinberg
| 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}}</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,Inc. | title = The Mineral Rheniite}}</ref> but is not an economically viable source of the element. Rhenium is widely spread through the [[Earth]]'s [[crust (geology)|crust]] at approximately 1 [[Parts-per notation|ppb]].
[[Chile]] has the world's largest reserves and was the leading producer as of 2005.<ref>{{cite web | url = http://minerals.usgs.gov/minerals/pubs/country/2005/cimyb05.pdf | publisher = [[United States Geological Survey]] | title = 2005 Minerals Yearbook: Chile}}</ref>
==Production==
Commercial rhenium is extracted from molybdenum roaster-flue gas obtained from copper-sulfide ores. Some molybdenum ores contain 0.002% to 0.2% rhenium. [[Rhenium(VII) oxide]] and [[perrhenic acid]] readily dissolve in water; they are leached from flue dusts and gasses and extracted by precipitating with [[potassium chloride|potassium]] or [[ammonium chloride]] as the [[perrhenate]] salts, and purified by [[recrystallization]].<ref name = patnaik>{{cite book | title = Handbook of Inorganic Chemicals | author = Pradyot Patnaik | publisher = [[McGraw-Hill]] | isbn = 0070494398 | pages = 790}}</ref> Total world production is between 40 and 50 tons/year; the main producers are in Chile, USA and Kazakhstan.<ref name="USGS_2008_summary">{{cite web | title = Rhenium | work = Mineral Commodity Summaries | publisher = U.S. Geological Survey | date = January 2008 | url = http://minerals.usgs.gov/minerals/pubs/commodity/rhenium/mcs-2008-rheni.pdf | format = PDF | accessdate = 2008-02-17}}</ref> Recycling of used [[Platinum|Pt]]-Re catalyst and special alloys allow the recovery of another 10 tons/year. Prices for the metal rose rapidly in early 2008, from a price of $1000-$2000 per [[kilogram|kg]] in 2003-2006 to over $10,000 in February 2008.<ref name="minormetals">{{cite web | title = MinorMetal prices | publisher = minormetals.com | date = | url = http://www.minormetals.com/ | accessdate = 2008-02-17}}</ref>
The metal form is prepared by reducing [[ammonium perrhenate]] with [[hydrogen]] at high temperatures:<ref name=patnaik/>
:2 NH<sub>4</sub>ReO<sub>4</sub> + 7 H<sub>2</sub> → 2 Re + 8 H<sub>2</sub>O + 2 NH<sub>3</sub>
== Isotopes ==
{{main|Isotopes of rhenium}}
Naturally occurring rhenium is 37.4% <sup>185</sup>Re, which is [[Stable isotope|stable]], and 62.6% <sup>187</sup>Re, which is [[Radionuclide|unstable]] but has a very long [[half-life]] which can be affected by its electron density<ref>http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/decay_rates.html How to Change Nuclear Decay Rates</ref><ref name=Bosch1996>{{cite journal
| doi = 10.1103/PhysRevLett.77.5190
| title = Observation of bound-state β– decay of fully ionized <sup>187</sup>Re:<sup>187</sup>Re-<sup>187</sup>Os Cosmochronometry
| author = Bosch
| year = 1996
| journal = Physical Review Letters
| volume = 77
| issue = 26
| pages = 5190–5193
}}</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 [[keV]]) is the lowest known among all [[radionuclide]]s. There are twenty-six other radioactive isotopes of rhenium recognized.
==Compounds==
{{more|:Category:Rhenium compounds}}
Rhenium is most available commercially as the [[sodium perrhenate|sodium]] and [[ammonium perrhenate]]s. It is also readily available as [[dirhenium decacarbonyl]]; these three compounds are common entry points to rhenium chemistry.
Various perrhenate salts may be easily converted to [[tetrathioperrhenate]] by the action of [[ammonium hydrosulfide]].<ref>{{cite journal | author = Goodman, J. T.; Rauchfuss, T. B., | title = Tetraethylammonium-tetrathioperrhenate [Et<sub>4</sub>N][ReS<sub>4</sub>] | journal = [[Inorganic Syntheses]] | year = 2002 | volume = 33 | pages = 107–110}}</ref>
{{main|Rhenium diboride}}
The hardest Boron compound is created synthetically. [[Rhenium diboride]] (ReB<sub>2</sub>) can actually scratch diamond, giving it a higher than 10 rank in the Mohs scale of mineral hardness and making it one of the three hardest substances known to man - the other two being [[ultrahard fullerite]] and [[aggregated diamond nanorods]].
Other compounds:
*[[Bromopentacarbonylrhenium(I)]]
*[[Pentacarbonylhydridorhenium]]
==References==
<!--This article uses the Cite.php citation mechanism. If you would like more information on how to add references to this article, please see http://meta.wikimedia.org/wiki/Cite/Cite.php -->
<div class="references-small">
*[http://periodic.lanl.gov/elements/75.html Los Alamos National Laboratory - Rhenium]
<references/>
</div>
== External links ==
{{Commons|Rhenium}}
{{wiktionary|rhenium}}
*[http://www.webelements.com/webelements/elements/text/Re/index.html WebElements.com - Rhenium]
*[http://www.pse-mendelejew.de/bilder/re.jpg pure Rhenium >99,99% picture in the element collection from Heinrich Pniok]
{{clear}}
{{Compact periodic table}}
[[Category:Chemical elements]]
[[Category:Transition metals]]
[[Category:Rhenium|*]]
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[[et:Reenium]]
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