Uranic acid

Uran-saure, /. uranic acid, -strahlen, m.pl. uranium rays, -tonbad, n. (Photog.) uranium toning bath, -tonung, /. uranium toning, uranuranig, a. uranoso-uranic, uranium(IV,VI). Uran-verbindung, /. uranium compound, -ver-starker, m. uranium intensifier. -vitriol, n. (Aftn.) johannite. 

Mucopolysaccharides Without Hexosamine or Uranic Acid Residues. 190... 

The organic fraction composition may influence the exchange capacity. A key contribution to the exchange capacity of humus is given by the carboxyl and phenolic hydroxyl functional groups. Under appropriate pH conditions, uranic acids in polysaccharides or carboxy-terminal structures in peptides can contribute to the... 

Tissue PG GAG Core protein No. total uranic acid) (% w/w) References"... 

Dermatan sulfate is an epimer of cbondroitin sulfate. The uranic acid residue in the repeal disaccharide is found as L-iduronic acid — [L-iduronate-a( 1 - 3)-iV-acetyl D-galactosamiiie- l(l->4)]rj —, The galactosamine residue is sulfated... 

Uranium Trioxide, Uranic Oxide, Uranic Anhydride, or Uranyl Oxide, UO3, is obtained when uranic acid, ammonium diuranate, or ammonium uranyl carbonate is heated to a temperature not exceeding 300° Cd When uranyl nitrate is similarly heated the product always contains basic nitrate, but if this product is heated in a current of oxygen at 500° C. it yields pure uranium trioxide. ... 

Uranium trioxide is slightly basic, but with the exception of uranium hexafluoride, the salts formed by interaction with acids still contain two-thirds of its oxygen in the form of the uranyl radical, compounds of the type UOjR g being produced. On the other hand, however, the oxide acts towards strong bases as an acid anhydride, similar to chromic anhydride, and produces stable uranates. In contact with water it readily forms uranic acid, U02(0H)2. ... 

Uranic acid, when amorphous, is a yellow powder, of density 5-92. In the crystalline form it yields, according to its mode of formation, rectangular orthorhombic tables or hexagonal crj-stals. When heated to 300° C. it loses water, - but it does not appear to be completely dehydrated until it begins to lose oxygen. ... 

The suhJiydrate, 2UOS.H2O, or pyro-uranic acid, H2U2O7, corresponding to the stable diuranates, has not as yet been shown to exist. 

Colloidal Uranic Acid.—By the addition of potash to a solution of... 

Potassium Peruranate, (K202)2.U04, is obtained by adding hydrogen peroxide to a solution of uranic acid or peruranic acid in aqueous caustic potash, and precipitating by means of alcohol. The salt is less stable than the corresponding sodium compound. Red peruranates of composition KjUOg and KaUOj.SHaO have been described. ... 

The dihydrate is formed by evaporation at ordinary temperature of an ethereal solution of the hexahydrate which has been dried with calcium nitrate or by crystallisation of the hexahydrate from concentrated nitric acid solution. It yields small lustrous plates, thick and square, probably rhombic, and possessing a green fluorescence. It melts at 179-3° C. It is much more stable than the trihydrate, and can be kept in a vacuum desiccator with caustic alkali or i hosphorus pentoxide without any loss of water. It dissolves readily in ether. If the dihydrate is heated in a current of carbon dio.xide at 98° C. a product corresponding very nearly in composition to the nioiiohydrate, U03(N03)3.H20, is obtained at 160° C. under the same conditions the ankydi ffus salt, U02(N03)2, is obtained. The latter may also be obtained by passing a current of dry nitric anhydride over the tri-hydrate carefully heated at 170° to 180° C. It is a yellow amorphous powder, readily soluble in water with c -olution of heat. It reacts violently with ether. When heated to 200° C. it decomposes and leaves a mixture of uranic acid, UO3.H2O, and uranic anhydride. ... 

Uranium and Hydrogen—Halogen and Oxyhalogen Compounds—Oxide. and. Hydroxides—Uranic Acid—Salts of Uranic Acid—Peruranic Acid and Peruranates—Compounds with Sulphur, Selenium, and Tellurium. 

When a solution of SeOg is evaporated the acid, HgSeOg, separates as hexagonal prisms. There are normal and acid selenites, and also superacid salts such as KH3(Se03)g. Heteropolyacids are formed with vanadic, molybdic and uranic acids. 

Mucopolysaccharide. A highly hydrated, jelly-like substance that provides intercellular lubrication (for multicellular organism) and structural support, and acts as a flexible cement. Bacteria use mucopolysaccharides to adhere to solid surfaces. Contains uranic acids and amino sugars. 

In neutral or masked alkaline solutions of uranyl salts, a quantitative precipitation of a red-brown product is obtained by adding 8-hydroxyquinoline (oxine). In contrast to other metal oxinates, which for the most part are inner complex phenolates, the uranium compound contains also a molecule of oxine as neutral part according to the formulation U02(CoHeNO)2 C9HeNOH.3 Probably this compoimd should not be viewed as uranyl oxinate but rather as the oxine ester of uranic acid, in other words as oxine uranate. 

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