Uranyl 3733058 220473039 2008-06-20T01:03:10Z 83.189.103.92 +[[de:Uranyl]] [[Image:Uranyl-3D-balls.png|right|thumb|[[Ball-and-stick model]] of [UO<sub>2</sub>]<sup>2+</sup>]] [[Image:Uranyl-ion-structure.png|right|thumb|The uranyl ion, showing the U-O bond order of 3]] [[Image:Uranyl-ion-diagram.png|right|thumb|Diagram of a uranyl ion. The formation of two short U-O bonds in the uranyl ion prevents the closer approach of a third [[oxygen]] atom.<ref name="cotton">{{cite book | author= Cotton, S | year= 1991 | title= Lanthanides and Actinides | | location= New York | publisher= Oxford University Press | pages= 128 }}</ref>]] The '''uranyl''' ion is the dipositive [[cation]] '''[UO<sub>2</sub>]<sup>2+</sup>''', which forms salts with acids. In this ion, [[uranium]] is in its +6 [[oxidation state]]. The other common oxidation state of uranium is uranium(IV), called [[uranous]]. The uranyl ion is the most common species encountered in the aqueous chemistry of uranium. Solid uranyl compounds are often colored red, yellow, orange or green. Like all uranium compounds, uranyl compounds are toxic. The toxicity of soluble uranyl salts is higher due to their faster incorporation into tissues. == Examples == Examples of uranyl compounds include: *[[Uranium trioxide]], UO<sub>3</sub> *[[Uranyl acetate]], UO<sub>2</sub>(C<sub>2</sub>H<sub>3</sub>O<sub>2</sub>)<sub>2</sub> *[[Uranyl ammonium carbonate]], UO<sub>2</sub>CO<sub>3</sub>·2(NH<sub>4</sub>)<sub>2</sub>CO<sub>3</sub> *[[Uranyl carbonate]], UO<sub>2</sub>CO<sub>3</sub> *[[Uranyl chloride]], UO<sub>2</sub>Cl<sub>2</sub> *[[Uranyl hydroxide]], UO<sub>2</sub>(OH)<sub>2</sub> or (UO<sub>2</sub>)<sub>2</sub>(OH)<sub>2</sub> also in aqueous *[[Uranyl nitrate]], UO<sub>2</sub>(NO<sub>3</sub>)<sub>2</sub> *[[Uranyl sulfate]], UO<sub>2</sub>SO<sub>4</sub> *[[Uranyl zinc acetate]], ZnUO<sub>2</sub>(CH<sub>3</sub>COO)<sub>4</sub> == Minerals == Such minerals occur in oxidised portions of [[Uraninite|uranium ore]] deposits. Common uranyl minerals include [[tyuyamunite]] (Ca(UO<sub>2</sub>)<sub>2</sub>V<sub>2</sub>O<sub>8</sub>·8H<sub>2</sub>O), [[autunite]] (Ca(UO<sub>2</sub>)<sub>2</sub>(PO<sub>4</sub>)<sub>2</sub>·8-12H<sub>2</sub>O), [[torbernite]] (Cu(UO<sub>2</sub>)<sub>2</sub> (PO<sub>4</sub>)·8-12H<sub>2</sub>O) and [[uranophane]] (H<sub>3</sub>O)<sub>2</sub>Ca (UO<sub>2</sub>)<sub>2</sub>(SiO<sub>4</sub>)·3H<sub>2</sub>O) ''(Hutchinson and Blackwell, 1984).'' Uranyl minerals, which contain uranium(VI) can help show the genesis of uranium deposits and the water-rock interactions that occur in uranium-rich mineral seams. == Chemistry == Uranium chemistry has traditionally revolved around the [[aqueous]] chemistry of the uranyl ion, and related molecular species. One important use of this chemistry is for preparation of [[uranium dioxide]] ceramic pellets that are used as the fuel in [[light water nuclear reactor]]s. Often the fuel materials start to break down chemically before the uranium is completely spent, and this too is an active area of investigation, as many of the corrosion products are of the uranyl group. == Uses == Partially soluble uranyl salts such as [[uranyl acetate]] are used for microscopy stains. These stains are used for electron and electromagnetic microscopy studies of DNA.<ref>Zobel, R. and Beer, M. (1961) [http://www.jcb.org/cgi/content/abstract/10/3/335 "ELECTRON STAINS : I. Chemical Studies on the Interaction of DNA with Uranyl Salts"] ''J. Biophys. and Biochem. Cytol.,'' vol. 10, pp. 335-346</ref> ==Structure== The geometry of the uranyl ion has been the subject of much debate. The close approach of two oxygen atoms to uranium, with each linear O-U-O bond from 1.7 to 1.9 Å, prevents the close approach of a third or more. ''d-p'' and ''f-p'' bonding have been suggested to explain the short U-O bonds.<ref name="cotton" /> ==Health and environmental issues== Uranyl nitrate is an oxidizing and highly toxic compound and should not be [[ingestion|ingested]]; it causes severe [[renal insufficiency]] and [[acute tubular necrosis]] and is a [[lymphocyte]] [[mitogen]]. Target organs include the [[kidney]]s, [[liver]], [[lungs]] and [[brain]]. Uranyl ion accumulation in tissues including gonocytes<ref>{{cite journal | author= Arfsten DP, Still KR, Ritchie GD | title= A review of the effects of uranium and depleted uranium exposure on reproduction and fetal development | journal= Toxicology and Industrial Health | year= 2001 | volume= 17 | pages=180–191 | doi= 10.1191/0748233701th111oa }}</ref> produces [[congenital disorder]]s, and in white blood cells causes immune system damage.<ref>{{cite journal | author= Schröder H, Heimers A, Frentzel-Beyme R, Schott A, Hoffman W | title= [http://www.cerrie.org/committee_papers/INFO_9-H.pdf Chromosome Aberration Analysis in Peripheral Lymphocytes of Gulf War and Balkans War Veterans] | journal= Radiation Protection Dosimetry | year= 2003 | volume= 103 | pages= 211–219 }}</ref> Uranyl compounds are also [[neurotoxin]]s. ==Combustion of uranium== Aerial oxidation of any uranium compound eventually results in the formation of a uranyl compound.<ref name="cotton" /> Uranyl ion contamination has been found on and around [[depleted uranium]] targets.<ref>{{cite journal | author= Salbu B, Janssens K, Linda OC, Proost K, Gijsels L, Danesic PR | title= Oxidation states of uranium in depleted uranium particles from Kuwait | journal= Journal of Environmental Radioactivity | year= 2004 | volume= 78 | pages= 125–135 | doi= 10.1016/j.jenvrad.2004.04.001 }}</ref> == References == <div class="references-small"><references /></div> [[Category:Neurotoxins]] [[Category:Oxycations]] [[Category:Teratogens]] [[Category:Uranyl compounds| ]] [[de:Uranyl]] [[pt:Uranilo]]