Uranyl hydroxide

Uranyl hydroxide
Uranyl hydroxide
Are common
Systematic ; name	Uranyl hydroxide
Traditional names	Uranium acid
Chem. formula	UO 2 (OH) 2
Rat formula	H 2 UO 4
Physical properties
condition	dark red crystals or yellow amorphous substance
Molar mass	304.04 g / mol
Density	5.926 g / cm³
Classification
Reg. CAS number
PubChem
Smiles
Inchi
UN number	2909
ChemSpider

Uranyl hydroxide is an inorganic compound, uranyl hydroxide with the formula UO ₂ (OH) ₂ (uranic acid H ₂ UO ₄ ), dark red crystals or a yellow amorphous substance insoluble in water forms crystalline hydrate .

Content

Getting

Uranium (VI) oxide dissolving in boiling water

{\mathsf {UO_{3}+H_{2}O\ {\xrightarrow {100^{o}C}}\ UO_{2}(OH)_{2}\downarrow }}

{\ displaystyle {\ mathsf {UO_ {3} + H_ {2} O \ {\ xrightarrow {100 ^ {o} C}} \ UO_ {2} (OH) _ {2} \ downarrow}}}

The decomposition of uranyl nitrate with ethanol :

{\mathsf {UO_{2}(NO_{3})_{2}\cdot 6H_{2}O\ {\xrightarrow {50-60^{o}C,C_{2}H_{5}OH}}\ UO_{2}(OH)_{2}\downarrow +2HNO_{3}+4H_{2}O}}

{\ displaystyle {\ mathsf {UO_ {2} (NO_ {3}) _ {2} \ cdot 6H_ {2} O \ {\ xrightarrow {50-60 ^ {o} C, C_ {2} H_ {5} OH}} \ UO_ {2} (OH) _ {2} \ downarrow + 2HNO_ {3} + 4H_ {2} O}}}

Decomposition of a dilute NaOH solution of uranium (VI) fluoride :

{\mathsf {UF_{6}+6NaOH\ {\xrightarrow {}}\ UO_{2}(OH)_{2}\downarrow +6NaF+2H_{2}O}}

{\ displaystyle {\ mathsf {UF_ {6} + 6NaOH \ {\ xrightarrow {}} \ UO_ {2} (OH) _ {2} \ downarrow + 6NaF + 2H_ {2} O}}}

Physical Properties

Uranyl hydroxide forms a yellow amorphous substance or dark red crystals of several modifications:

α-UO ₂ (OH) ₂ — rhombic syngony , space group C 2cb , cell parameters a = 0.4242 nm, b = 1.0302 nm, c = 0.6868 nm.

Forms a crystalline hydrate of the composition UO ₂ (OH) ₂ • H ₂ O.

Not soluble in water, p PR = 14.70.

Chemical Properties

Anhydrous base is obtained by drying crystalline hydrate :

{\mathsf {UO_{2}(OH)_{2}\cdot H_{2}O\ {\xrightarrow {100^{o}C}}\ UO_{2}(OH)_{2}+H_{2}O}}

{\ displaystyle {\ mathsf {UO_ {2} (OH) _ {2} \ cdot H_ {2} O \ {\ xrightarrow {100 ^ {o} C}} \ UO_ {2} (OH) _ {2} + H_ {2} O}}}

Decomposes on heating:

{\mathsf {UO_{2}(OH)_{2}\ {\xrightarrow {160^{o}C}}\ U_{2}O_{5}(OH)_{2}+H_{2}O}}

{\ displaystyle {\ mathsf {UO_ {2} (OH) _ {2} \ {\ xrightarrow {160 ^ {o} C}} \ U_ {2} O_ {5} (OH) _ {2} + H_ { 2} O}}}

{\mathsf {UO_{2}(OH)_{2}\ {\xrightarrow {350-400^{o}C}}\ UO_{3}+H_{2}O}}

{\ displaystyle {\ mathsf {UO_ {2} (OH) _ {2} \ {\ xrightarrow {350-400 ^ {o} C}} \ UO_ {3} + H_ {2} O}}}

Reacts with acids :

{\mathsf {UO_{2}(OH)_{2}+2HCl\ {\xrightarrow {}}\ UO_{2}Cl_{2}+2H_{2}O}}

{\ displaystyle {\ mathsf {UO_ {2} (OH) _ {2} + 2HCl \ {\ xrightarrow {}} \ UO_ {2} Cl_ {2} + 2H_ {2} O}}}

With concentrated solutions of alkalis forms diuranates salts:

{\mathsf {2UO_{2}(OH)_{2}+2NaOH\ {\xrightarrow {}}\ Na_{2}U_{2}O_{7}\downarrow +3H_{2}O}}

{\ displaystyle {\ mathsf {2UO_ {2} (OH) _ {2} + 2NaOH \ {\ xrightarrow {}} \ Na_ {2} U_ {2} O_ {7} \ downarrow + 3H_ {2} O}} }

Literature

Chemical Encyclopedia / Editorial: Zefirov N.S. et al. - M .: Big Russian Encyclopedia, 1998. - V. 5. - 783 p. - ISBN 5-85270-310-9 .
Chemistry Handbook / Editorial: Nikolsky B.P. et al. - 3rd ed., rev. - L .: Chemistry, 1971. - T. 2. - 1168 p.
Lidin R.A. and other Chemical properties of inorganic substances: Textbook. manual for universities. - 3rd ed., Rev. - M .: Chemistry, 2000 .-- 480 p. - ISBN 5-7245-1163-0 .