Lithium uranate

Lithium Uranate, LiaUO, is obtained by fusing together lithium chloride and urano-uranic oxide. It is less stable towards water than the other alkali uranates. 

Reactions in Molten Salt Solutions. I. Uranate and Neptunate Formation in Molten Lithium Nitrate-Sodium Nitrate, W.T. Camall, S.J. Neufeldt, and A. Walker, Inorg. Chem. 4, 1808-1813 (1965). 

Benzo[6]furan is cleaved on reduction with excess sodium in liquid ammonia, followed by quenching with ammonium chloride or methanol, to produce 2-ethylphenol (69%). 2-Methyl- and 2-phenyl-benzo[6]furan similarly yield 2-propylphenol (54%) and 2-(2-phenylethyl)phenol (45%) (59JA2795). Similarly, 5-methoxybenzo[6]furan, on reduction with 2 mol of lithium and a limited amount of t- butanol, gives the cleavage product, but by operating with 2 mol each of lithium and t- butanol, 5-methoxy-2-methylbenzo[6 ]furan supplies the 2,3-dihydro compound. With excess of the alcohol, however, 5-methoxy-2,3,4,7-tetrahydrobenzo[6]f uran is secured so that the reduction is stepwise (67JOC2794). 

Borat Phenyl-trihydro-Lithium-Salz XIII/3b, 821 Tris-pi 5-cyclopenta dieny l -uran- Salz XIII/3b, 828 Borinat 1-Methyl- (Tl-Salz) XIII/3a, 313... 

TJranyl nitrate forms double salts of the type E U02(N03)3, where R =K, NH4, Rb, Cs, or Tl. They may be prepared by crystallising a solution of the mixed nitrates in concentrated nitric acid or by crystallisation from a solution of the alkali uranate in excess of nitric acid. The crystals are all anhydrous, and in the case of the potassium salt are orthorhombic, whilst the rubidium and caesium salts are rhombo-hedral and isomorphous with each other. The ammonium salt yields both orthorhombic and rhombohedral crystals. All exhibit a yellowish-green fluorescence they are liygroscopic and readily decomposed by water into their components. The thallium salt is particularly unstable, being decomposed in moist air. On the other hand, the rubidium salt dissolves in water at 80° C. without decomposition. The corresponding salts of sodium, lithium, or of divalent metals have not been prepared. 

Table III. Schematic Representation of Lithium and Sodium Uranates (VI) and Transuranates (VI)...

The product obtained from the lithium nitrate-potassium nitrate eutectic is neither identifiable as the diuranate (U2O7 ) or uranate (UO4 ) species, nor as a mixture composed of each of these species. To date, the x-ray powder diffraction pattern has not been identified with any known compound. It is interesting to note the ratios of the alkali metals for this system, however approximately a 2 1 atomic... 

Figure 11 shows the atomic configurations of the uranate centres proposed by Runciman (a) and by Kaplyanskii (b). In contrast to these proposals Pant et al. ) ascribe the luminescence properties to square-planar U04-groups. Recently, E.P.R. measurements have been performed on X- or 7-irradiated crystals of uranium-activated lithium fluoride and uranium-activated sodium fluoride " ). The authors propose (UOsF) ), (UOs—or (UOs)" ) to be the uranium centres, containing pentavalent uranium. 

A mixture of alkali uranate (VI) and UO3 (1 1 mole ratio) is heated in evacuated, sealed quartz ampoules at 650-750 C. The ampoules are opened at intervals of 10-20 hours, the reaction product is regroimd to a fine powder, and the heating is resumed using a new ampoule. The reaction is complete in 75-100 hours the lithium compound forms in a somewhat shorter time and at a somewhat lower temperature. 

Treatment of ) -hydroxyketones or j8-trimethylsilyloxyketones with trimethylsilyldiazomethyl-lithium yields 2,3-dihydrof urans, which can be dehydrogenated to furans with mangenese dioxide (Scheme 18) <94SL46i>. Obviously a carbene is an intermediate in the first step of the reaction. 

Uranium, unlike thorium, has an accessible trivalent oxidation state. It has been shown that uranocene can be reduced by lithium naph-thalide to the bis([8]annulene)uranate(III) anion.23 The same complex can be synthesized by the reaction of two equivalents of [8]annulene dianion with one equivalent of uranium trichloride.23... 

CioHi3LiOioU 4 H2O, Lithium glutarato(hydrogenglutarato)dioxo-uranate(VI) tetrahydrate, 45B, 1108 C oH1aCuNaOu, Bis(imidazole)copper(11) diacetate, 43B, 1226 C1 oH 1 6C1ijCu2NuO 1 0 f Copper chloroacetate - urea, 40B, 866 CioHi8Cli,Oi,Re2, Tetrachlorobis M (2,2-dimethylpr opionato)di rhenium, 45B, 1109... 

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