Uranyl


Uranyl

The uranyl ion is the dipositive cation [UO2] 2+, 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, UO3
*Uranyl acetate, UO2(C2H3O2)2
*Uranyl ammonium carbonate, UO2CO3·2(NH4)2CO3
*Uranyl carbonate, UO2CO3
*Uranyl chloride, UO2Cl2
*Uranyl hydroxide, UO2(OH)2 or (UO2)2(OH)2 also in aqueous
*Uranyl nitrate, UO2(NO3)2
*Uranyl sulfate, UO2SO4
*Uranyl zinc acetate, ZnUO2(CH3COO)4

Minerals

Such minerals occur in oxidised portions of uranium ore deposits. Common uranyl minerals include tyuyamunite (Ca(UO2)2V2O8·8H2O), autunite (Ca(UO2)2(PO4)2·8-12H2O), torbernite (Cu(UO2)2 (PO4)·8-12H2O) and uranophane (H3O)2Ca (UO2)2(SiO4)·3H2O) "(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 reactors. 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. [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]

tructure

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.

Health and environmental issues

Uranyl nitrate is an oxidizing and highly toxic compound and should not be ingested; it causes severe renal insufficiency and acute tubular necrosis and is a lymphocyte mitogen.

Target organs include the kidneys, liver, lungs and brain. Uranyl ion accumulation in tissues including gonocytes [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 ] produces congenital disorders, and in white blood cells causes immune system damage. [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 ] Uranyl compounds are also neurotoxins.

Combustion of uranium

Aerial oxidation of any uranium compound eventually results in the formation of a uranyl compound. Uranyl ion contamination has been found on and around depleted uranium targets. [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 ]

References


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Look at other dictionaries:

  • Uranyl — U ra*nyl, n. [Uranium + yl.] (Chem.) The radical {UO2}, conveniently regarded as a residue of many uranium compounds. [1913 Webster] …   The Collaborative International Dictionary of English

  • Uranyl — Uranyl, von Peligot zur Erklärung der Uranverbindungen hypothetisch unter der Formel U2 O2 angenommenes, zusammengesetztes Radical, s.u. Uran …   Pierer's Universal-Lexikon

  • Uranyl — Uranyl, s. Uran …   Meyers Großes Konversations-Lexikon

  • uranyl — [yoor′ə nil΄] n. [ URAN(IUM) + YL] the divalent radical UO2, present in many compounds of uranium …   English World dictionary

  • Uranyl — Stäbchenmodell von [UO2]2+. Das Uranylion mit Veranschaulichung des dreifachen U O Bindungsverhältnisses …   Deutsch Wikipedia

  • uranyl — noun the bivalent radical UO2 which forms salts with acids • Syn: ↑uranyl group, ↑uranyl radical • Hypernyms: ↑group, ↑radical, ↑chemical group • Substance Holonyms: ↑uranyl oxalate …   Useful english dictionary

  • uranyl — uranilas statusas T sritis chemija apibrėžtis Katijonas. formulė UO₂²⁺ atitikmenys: angl. uranyl rus. уранил ryšiai: sinonimas – dioksouranas (2+) …   Chemijos terminų aiškinamasis žodynas

  • uranyl — noun Etymology: International Scientific Vocabulary, from New Latin uranium + International Scientific Vocabulary yl Date: 1850 a divalent radical UO2 …   New Collegiate Dictionary

  • uranyl — uranylic, adj. /yoor euh nil/, n. Chem. the bivalent ion UO2+2, or the group UO2, which forms salts with acids. [1840 50; URAN(IUM) + YL] * * * …   Universalium

  • uranyl — noun The divalent radical UO, conveniently regarded as a residue of many uranium compounds …   Wiktionary


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