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The metal uranium forms several oxides: Uranium dioxide or uranium(IV) oxide (UO 2, the mineral uraninite or pitchblende) Diuranium pentoxide or uranium(V) oxide (U 2 O 5) Uranium trioxide or uranium(VI) oxide (UO 3) Triuranium octoxide (U 3 O 8), the most stable uranium oxide; yellowcake typically contains 70 to 90 percent triuranium octoxide)
The most common forms of uranium oxide are triuranium octoxide (U 3 O 8) and UO 2. [3] Both oxide forms are solids that have low solubility in water and are relatively stable over a wide range of environmental conditions. Triuranium octoxide is (depending on conditions) the most stable compound of uranium and is the form most commonly found in ...
Uranium dioxide or uranium(IV) oxide (UO 2), also known as urania or uranous oxide, is an oxide of uranium, and is a black, radioactive, crystalline powder that naturally occurs in the mineral uraninite. It is used in nuclear fuel rods in nuclear reactors. A mixture of uranium and plutonium dioxides is used as MOX fuel.
For example, a mixture of 7% plutonium and 93% natural uranium reacts similarly, although not identically, to low-enriched uranium fuel (3 to 5% uranium-235). MOX usually consists of two phases, UO 2 and PuO 2, and/or a single phase solid solution (U,Pu)O 2.
Uranyl nitrate is a water-soluble yellow uranium salt with the formula UO 2 (NO 3) 2 · n H 2 O.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 presence of oxygen (O 2), uranium dioxide (UO 2) is oxidized to U 3 O 8, whereas uranium trioxide (UO 3) loses oxygen at temperatures above 500 °C and is reduced to U 3 O 8. The compound can be produced by any one of three primary chemical conversion processes, involving either uranium tetrafluoride (UF 4 ) or uranyl fluoride (UO 2 F 2 ...
The compound can be prepared by treating uranium trioxide]] with acetic acid: UO 3 + 2 CH 3 COOH + H 2 O → UO 2 (CH 3 COO) 2 ·2H 2 O. The acetate ligands of uranyl acetate can be replaced to give a variety of uranyl complexes. [6] Uranyl acetate can also be reduced by zinc to give the uranium(IV) acetate (U(OAc) 4). [7]
Uranium-235 (235 U or U-235) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile isotope that exists in nature as a primordial nuclide. Uranium-235 has a half-life of 703.8 million years.