Uranyl nitrate

Uranyl nitrate
IUPAC name (T-4)-bis(nitrato-κO)dioxouranium
Other names Uranium nitrate
Identifiers
CAS number	10102-06-4 Y
ChemSpider	22177973 Y
Jmol-3D images	Image 1
SMILES [N+](=O)([O-])O[U-2](=O)(=O)O[N+](=O)[O-]
InChI InChI=1S/2NO3.2O.U/c2*2-1(3)4;;;/q2*-1;;; Y Key: QWDZADMNIUIMTC-UHFFFAOYSA-N Y InChI=1/2NO3.2O.U/c2*2-1(3)4;;;/q2*-1;;;/rN2O8U/c3-1(4)9-11(7,8)10-2(5)6/q-2 Key: QWDZADMNIUIMTC-FNIZAZFDAM
Properties
Molecular formula	UO2(NO3)2
Molar mass	394.04 g/mol
Appearance	yellow-green solid hygroscopic
Density	2.81 g/cm3
Melting point	60 °C
Boiling point	118 °C decomp.
Solubility in water	~660 g/L
Solubility in tributyl phosphate	soluble
Hazards
MSDS	External MSDS
EU Index	092-002-00-3
EU classification	Very toxic (T+) Dangerous for the environment (N)
R-phrases	R26/28, R33, R51/53
S-phrases	(S1/2), S20/21, S45, S61
Flash point	Non-flammable
Related compounds
Other anions	Uranyl chloride Uranyl sulfate
Y nitrate (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Uranyl nitrate (U O₂(N O₃)₂) is a water soluble yellow uranium salt. The yellow-green^[1] crystals of uranium nitrate hexahydrate are triboluminescent.

Uranyl nitrate can be prepared by reaction of uranium salts with nitric acid. It is soluble in water, ethanol, acetone, and ether, but not in benzene, toluene, or chloroform.

Uses

During the first half of the 19th century, many photosensitive metal salts had been identified as candidates for photographic processes, among them uranyl nitrate. The prints thus produced were alternately referred to as uranium prints, urbanities, or more commonly uranotypes. The first uranium printing processes were invented by a Scotsman, J. Charles Burnett, between 1855 and 1857, and used this compound as the sensitive salt. Burnett, authored an 1858 article comparing "Printing by the Salts of the Uranic and Ferric Oxides" The basis for the process lies in the ability of the uranyl ion to pick up two electrons and reduce to the lower oxidation state of uranium(IV) under ultraviolet light. Uranotypes can vary from print to print from a more neutral, brown russet to strong Bartolozzi red, with a very long tone grade. Surviving prints are slightly radioactive, a property which serves as a means of non-destructively identifying them. Several other more elaborate photographic processes employing the compound sprung up and vanished throughout the second half of the 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 in the face of the superior sensitivity and practical advantages of the silver halides. Nevertheless between the 1930s through the 1950s Kodak Books still described a uranium toner (Kodak T-9) using uranium nitrate hexahydrate. Some alternative process photographers including artists Blake Ferris & Robert Schramm continue to make uranotype prints today.

Along with uranyl acetate it is used as a negative stain for viruses in electron microscopy; in tissue samples it stabilizes nucleic acids and cell membranes.

Uranyl nitrate was used to fuel Aqueous Homogeneous Reactors in the 1950s. However it proved too corrosive in this application, and the experiments were abandoned.

Uranyl nitrate is important for nuclear reprocessing; it is the compound of uranium that results from dissolving the decladded spent nuclear fuel rods or yellowcake in nitric acid, for further separation and preparation of uranium hexafluoride for isotope separation for preparing of enriched uranium.

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. It also represents a severe fire and explosion risk when heated or subjected to shock in contact with oxidizable substances.

External links

• URANIUM DAYS: Notes On Uranium Photography (2007 archive from archive.org)
• Chemical Database – Uranyl nitrate, solid

References

1. ^ Roberts, D.E. and Modise, T.S. (2007). Laser removal of loose uranium compound contamination from metal surfaces. Applied Surface Science 253, 5258–5267.