Uranates are chemical compounds of uranium oxides formed by their interaction with oxides of other chemical elements that exhibit more basic properties.
Content
Physical and chemical properties
Uranates should be considered as salts of uranium H 2 UO 4 , non-existent diuran H 2 U 2 O 7 and polyuran H 2 U n O 3n + 1 acids. Alkali metal uranates have the composition M 2 UO 4 , as well as M 2 U 2 O 7 and 2M 2 O β’ UO 2 . Alkaline earth metals and metals forming doubly charged cations (Cu, Pb, Mn, Fe) are capable of forming uranates of the composition MUO 4 , MU 2 O 7 , M 3 UO 6 .
Uranates are yellow or yellow-orange solid substances. In water, they are insoluble, but soluble in mineral acids. Decomposed by the action of carbonates.
Receiving and applying
Obtaining uranates consists in sintering uranium oxides with oxides of other elements in a stoichiometric ratio. Diuranates can be obtained by precipitation from aqueous solutions of U (VI) salts. During sintering, it is also possible to obtain uranates of complex composition (3Na 2 O β’ 7UO 3 ) and uranates with a uranium atom in a different oxidation state (NaUO 5 ). Precipitation can produce ammonium polyuranate, for example, (NH 4 ) 2 U 4 O 17 . Soluble peruranates, for example, sodium peruranate Na 2 UO 5 , can be obtained by reacting uranium oxides with a solution of hydrogen peroxide in an alkaline medium.
U (VI) uranates are used in the processes of obtaining uranium and its compounds. In particular, uranium oxides can be obtained by precipitation and further calcination of ammonium diuranate (NH 4 ) 2 U 2 O 7 .
Being in nature
Uranates can occur in nature. These include, for example, the mineral clarkite Na 2 U 2 O 7 .
Danger
All uranates are poisonous, like all other uranium compounds.
Literature
- Chemical Encyclopedia / Editorial: Zefirov N.S. et al. - M .: Big Russian Encyclopedia, 1998. - V. 5. - 783 p. - ISBN 5-85270-310-9 .