|
A uranate is a ternary oxide involving the element uranium in one of the oxidation states +4, +5 or +6. A typical chemical formula is MxUyOz, where M represents a cation. The uranium atom in uranates(VI) has two short, co-linear, U-O bonds and either four or six more next nearest oxygen atoms.〔 The structures are infinite lattice structures with the uranium atoms linked by bridging oxygen atoms. "Ammonium diuranate" is an intermediate in the production of uranium oxide nuclear fuels. ==Synthesis== A method of general applicability involves combining two oxides in a high temperature reaction. For example, :Na2O + UO3 → Na2UO4 Another method is the thermal decomposition of a complex, such as an acetate complex. For example, microcrystalline barium diuranate, BaU2O7 was made by thermal decomposition of barium uranyl acetate at 900 °C. :Ba()2 → BaU2O7 + ... (ac=CH3CO2−) Uranates are insoluble in water and other solvents, so pure samples can only be obtained by careful control of reaction conditions.〔 Naturally occurring uranates are rare and always occur as secondary minerals. Examples include curite, becquerelite and soddyite named after prominent radiochemists Pierre Curie and Marie Curie, Henri Becquerel and Frederick Soddy, respectively. Uranates can be prepared by adding alkali to an aqueous solution of a uranyl salt. However, the composition of the precipitate that forms is variable and depends on the chemical and physical conditions used. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「uranate」の詳細全文を読む スポンサード リンク
|