Uranyl nitrate is a water-soluble yellow uranium salt with the formulaUO2(NO3)2 ·n H2O. The hexa-, tri-, and dihydrates are known.[3] The compound is mainly of interest because it is an intermediate in the preparation of nuclear fuels. In the nuclear industry, it is commonly referred to as yellow salt.
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| Names | |
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| IUPAC name (T-4)-bis(nitrato-κO)dioxouranium | |
| Other names Uranium nitrate, Yellow salt | |
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| ECHA InfoCard | 100.030.229 |
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| Properties | |
| UO2(NO3)2 | |
| Molar mass | 394.04 g/mol |
| Appearance | yellow-green solid hygroscopic |
| Density | 3.5 g/cm3 (dihydrate)[1] |
| Melting point | 60.2 °C (140.4 °F; 333.3 K) |
| Boiling point | 118 °C (244 °F; 391 K) (decomposition) |
| g/100g H2O: 98 (0°C), 122 (20°C), 474 (100°C)< | |
| Solubility intributyl phosphate | soluble |
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| Flash point | Non-flammable |
| Lethal dose or concentration (LD, LC): | |
LDLo (lowest published) | 12 mg/kg (dog, oral) 238 (cat, oral)[2] |
| Safety data sheet (SDS) | External MSDS |
| Related compounds | |
Otheranions | Uranyl chloride Uranyl sulfate |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Uranyl nitrate can be prepared by reaction of uranium salts withnitric acid. It is soluble inwater,ethanol, andacetone. As determined byneutron diffraction, the uranyl center is characteristically linear with short U=O distances. In the equatorial plane of the complex are six U-O bonds to bidentate nitrate and two water ligands. At 245pm, these U-O bonds are much longer than the U=O bonds of the uranyl center.[1]
Uses
editProcessing of nuclear fuels
editUranyl nitrate is important fornuclear reprocessing. It is the compound of uranium that results from dissolving the decladded spentnuclear fuel rods oryellowcake in nitric acid, for further separation and preparation ofuranium hexafluoride forisotope separation for preparing ofenriched uranium. A special feature of uranyl nitrate is its solubility intributyl phosphate (PO(OC4H9)3), which allows uranium to be extracted from the nitric acid solution. Its high solubility is attributed to the formation of the lipophilic adduct UO2(NO3)2(OP(OBu)3)2.[citation needed]
Archaic photography
editDuring the first half of the 19th century, manyphotosensitive metal salts had been identified as candidates forphotographic processes, among them uranyl nitrate. The prints thus produced were called uranium prints or uranotypes.The first uranium printing processes were invented by Scotsman J. Charles Burnett between 1855 and 1857, and used this compound as the sensitive salt. Burnett authored a 1858 article comparing "Printing by the Salts of the Uranic and Ferric Oxides"The process employs the ability of the uranyl ion to pick up twoelectrons and reduce to the loweroxidation state of uranium(IV) underultraviolet light.Uranotypes can vary from print to print from a more neutral, brown russet to strongBartolozzi red, with a very long tone grade. Surviving prints are slightlyradioactive, a property which serves as a means of non-destructively identifying them.Several other more elaborate photographic processes employing the compound appeared and vanished during the second half of the 19th century with names like Wothlytype, Mercuro-Uranotype and the Auro-Uranium process. Uranium papers were manufactured commercially at least until the end of the 19th century, vanishing due to the superior sensitivity and practical advantages ofsilver halides. From the 1930s through the 1950sKodak Books described a uranium toner (Kodak T-9) using uranium nitrate hexahydrate.[citation needed]
Stain for microscopy
editAlong withuranyl acetate it is used as anegative stain forviruses inelectron microscopy; in tissue samples it stabilizesnucleic acids andcell membranes.[citation needed]
As a reagent
editUranyl nitrates are common starting materials for the synthesis of other uranyl compounds because the nitrate ligand is easily replaced by other anions. It reacts with oxalate to giveuranyl oxalate. Treatment withhydrochloric acid givesuranyl chloride.[4]
Health and environmental issues
editUranyl nitrate is an oxidizing and highly toxic compound. When ingested, it causes severechronic kidney disease andacute tubular necrosis and is alymphocytemitogen. Target organs include thekidneys,liver,lungs andbrain. It also represents a severe fire and explosion risk when heated or subjected to shock in contact with oxidizable substances.[citation needed]
References
edit- ^abMueller, Melvin Henry; Dalley, N. Kent; Simonsen, Stanley H. (1971). "Neutron Diffraction Study of Uranyl Nitrate Dihydrate".Inorganic Chemistry.10 (2):323–328.doi:10.1021/ic50096a021.
- ^"Uranium (soluble compounds, as U)".Immediately Dangerous to Life or Health Concentrations (IDLH).National Institute for Occupational Safety and Health (NIOSH).
- ^Peehs, Martin; Walter, Thomas; Walter, Sabine; Zemek, Martin (2007). "Uranium, Uranium Alloys, and Uranium Compounds".Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH.doi:10.1002/14356007.a27_281.pub2.ISBN 978-3-527-30673-2.
- ^F. Hein, S. Herzog (1963). "Uranyl Chloride". In G. Brauer (ed.).Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 2. NY, NY: Academic Press. p. 1439.