Cerium , monohydrate

The coordination geometry in anhydrous Th(CF3COCHCOMe)4 is a 1111 ( )4-422) antiprism 74 the structure of the monohydrate has been discussed earlier (p. 1144). Th[CF3COCHCO(2-C4H3S)]4 is isostructural with the cerium(IV), uranium(IV) and plutonium(IV) analogues. The coordination polyhedron is a distorted dodecahedron in which the four ligands span the two perpendicular trapezoids of the dodecahedron.75 In the complexes M(n-C3F7COCHCOBut)4, the thorium(IV), uranium(IV) and neptunium(IV) compounds are isomorphous, but the plutonium compound is not. 

Cerium(lll) chloride monohydrate Cerium chloride (CeCl3), monohydrate (64332-99-6), 76, 228... 

Reaction of anhydrous cerium(iii) chloride with RLi reagents affords organocerium compounds The cerium chloride is prepared by heating CeCl3(H20)7 in vacuo up to 140 °C and is in fact a monohydrate [CeCl3(H20)], see W.J. Evans, J.D. Feldman, and J.W. Ziller, J. Am. Chem. Soc., 1996,118,4581. Reaction is carried out at -78 °C, as decomposition is rapid at 0 °C, especially if a /3-hydrogen is present in the R group. The exact nature of the cerium species is uncertain. 

The preparation of anhydrous cerium(lll) chloride4 is necessary to obtain a satisfactory result. For example, the use of cerium(lll) chloride monohydrate in the same reaction causes a significant lowering of the yield (34%) of the desired alcohol (the recovery of the starting ketone 54%). The use of the reverse addition procedure (see Method B in the Table) also resulted in the formation of the alcohol in poor yield (36% the recovery of the ketone 58%). 

Cerium sulfide Cobalt aluminum oxide D C Red No. 7 Flavanthrone Indanthrone Iron oxide black Iron oxide brown Iron oxide red Iron oxide yellow Iron oxide yellow monohydrate... 

Zirconium oxide in a monohydrated form is found to adsorb phosphate ion from wastewaters (Suzuki and Fujii, 1987). Cerium oxide is effective in adsorption of fluoride ion in industrial wastewaters. 

Hydrated phases are known for both the tetrahalides and the dihalides, but neither has been extensively characterized. Cerium tetrafluoride monohydrate, CeF4 H20, has been prepared by several procedures (Asker and Wylie, 1964). The product of digesting Ce02 in concentrated aqueous HF solution at 100-130° is CeF4.o-l.OH2O, while that obtained by reaction of the dioxide with anhydrous HF is CeF4.o-O.8H2O. Powder X-ray diffraction data are reported the structure is unknown and different from that of the anhydrous tetrafluoride. 

The RbR(S04)2 compounds can be prepared either by isothermal evaporation of an Rb2S04-R2(S04)3 aqueous solution at 70°C or by a solid-state synthesis. The former method can be applied only for the lighter rare earths (La Eu) for with the heavier rare earths the monohydrate forms under these conditions (Sarukhanyan et al., 1982, 1984d). The recent studies by Prokofev et al. (1979) and Sarukhanyan et al. (1983, 1984b,d) have established the existence of three main structure types (a) monoclinic (La - Tb), (b) orthorhombic (Pr Er), and (c) monoclinic (Dy--Lu). In addition, unpublished data indicate that lanthanum and cerium form still another polymorph (Prokofev, 1980). Owing to its smaller ionic size, scandium probably forms a sulfate with a different structure and indeed a hexagonal structure has been proposed on the basis of powder diffraction patterns (Ivanov-Emin et al., 1966 Erametsa and Haukka, 1968). 

The anhydrous rare earth iodates of structure type HI and those dehydrated from monohydrates are hygroscopic. The solubility of R(I03)3 (R = La, Ce, Sm, Eu) in water varies between 0.3 and 2.6mmol/dm, being lowest for samarium and highest for cerium (Chloupek et al., 1932 Monk, 1951b Laurie and Monk, 1963 Shklovskaya et al., 1977). The properties of the water solutions have been studied by Firsching and Paul (1966). 

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