Triuranium octoxide

Triuranium octoxide
Triuranium octoxide
Identifiers
CAS number 1317-99-3
Properties
Molecular formula U3O8
Molar mass 842.1 g/mol
Melting point

1150°C

Boiling point

decomposes to UO2 at 1300 °C

Solubility in other solvents Insoluble in water;

Soluble in nitric and sulfuric acids.

 YesY (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Triuranium octoxide (U3O8) is a compound of uranium. It is present as an olive green to black, odorless solid. In spite of its color, it is one of the more popular forms of yellowcake and is shipped between mills and refineries in this form.

Triuranium octoxide occurs naturally as the olive-green-colored mineral pitchblende. U3O8 is readily produced from UF6 and has potential long-term stability in a geologic environment. In the presence of oxygen (O2), uranium dioxide (UO2) is oxidized to U3O8, whereas uranium trioxide (UO3) loses oxygen at temperatures above 500°C and is reduced to U3O8. The compound can be produced by any one of three primary chemical conversion processes, involving either uranium tetrafluoride (UF4) or uranyl fluoride (UO2F2) as intermediates. It is generally considered to be the more attractive form for disposal purposes because, under normal environmental conditions, U3O8 is one of the most kinetically and thermodynamically stable forms of uranium and also because it is the form of uranium found in nature. Its particle density is 8.3 g cm−3.

Solid state structure

The solid is a layered structure where the layers are bridged by oxygen atoms, each layer contains uranium atoms which are in different coordination environments in the above diagram these are shown in plum and green.

Bond valence study

Using a 6Å x 6Å x 6Å box with the uranium atom in the centre the bond valence calculation was performed for both U1 and U2 in solid.[1] It was found using the parameters for U(VI) that the calculated oxidation states for U1 and U2 are 5.11 and 5.10. Using the parameters for U(IV) the calculated oxidation states are 5.78 and 5.77 respectively for U1 and U2. These study suggests that all the uranium atoms have the same oxidation state, so that the oxidation states are disordered through the lattice.

References


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • Nuclear reprocessing — technology was developed to chemically separate and recover fissionable plutonium from irradiated nuclear fuel.[1] Reprocessing serves multiple purposes, whose relative importance has changed over time. Originally reprocessing was used solely to… …   Wikipedia

  • Yellowcake — For the falsified documents, see Yellowcake forgery. Chembox new Name = Yellowcake ImageFile = Yellowcake.jpg ImageSize = 250px OtherNames = urania Section1 = Chembox Identifiers CASNo = Section2 = Chembox Properties Formula = variable, see text… …   Wikipedia

  • Uranium trioxide — IUPAC name Uranium trioxide Uranium(VI) oxide …   Wikipedia

  • Kazatomprom — Infobox Company company name=KazatompromКазатомпром company logo= type=Government owned corporation foundation=1997 location= Almaty, Kazakhstan key people = Moukhtar Dzhakishev, President num employees=30,000 products= Uranium,… …   Wikipedia

  • uranium processing — Introduction       preparation of the ore for use in various products.       Uranium (U), although very dense (19.1 grams per cubic centimetre), is a relatively weak, nonrefractory metal. Indeed, the metallic properties of uranium appear to be… …   Universalium

  • Mining industry of Niger — Known and exploited Mineral resources of Niger, data derived from US Geological Survey. Colored circles represent current mining centers. Unexploited but proved resources in parentheses. * Gold: Au * Coal: C * Diamond: Dm * Iron ore: Fe *… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”