Europium preparation

The purity of a europium preparation may be tested by observing its absorption spectrum. In a 5- to 10-cm. layer a dilute solution of a europium(III) salt shows two sharp bands at about 4650 and 5350 A. In a chloride solution these bands are of about equal intensity. In an acetate solution the latter band is approximately as strong as in the chloride solution, but the band at 4650 A. is greatly enhanced. A number of weaker bands are also visible in concentrated europium(III) solutions. 

The purity of a europium preparation may also be checked iodometrically by titrating a europium(II) chloride solution prepared from a weighed portion of the oxide. 

The first described organometallic compound of a rare earth element in the oxidation state + 2 was dicyclopentadienyl europium, prepared by E.O. Fischer and H. Fischer (1964) by reacting europium with cyclopentadiene in liquid ammonia. Ytterbium metal reacts in the same way (E.O. Fischer and H. Fischer, 1965b). By... 

Europium(TTI) salts are typical lanthanide derivatives. Europium(ll) salts are pale yellow in colour and are strong reducing agents but stable in water. EuX2 are prepared from EuX -hEu (X=C1, Br, I) or EuFa + Ca EuCl2 forms a dihydrale. EUSO4 is prepared by electrolytic reduction of Eu(III) in sulphuric acid. Eu(II) is probably the most stable +2 stale of the lanthanides... 

Europium is now prepared by mixing EU2O3 with a 10%-excess of lanthanum metal and heating the mixture in a tantalum crucible under high vacuum. The element is collected as a silvery-white metallic deposit on the walls of the crucible. 

Electrical and Electronic Applications. Silver neodecanoate [62804-19-7] has been used in the preparation of a capacitor-end termination composition (110), lead and stannous neodecanoate have been used in circuit-board fabrication (111), and stannous neodecanoate has been used to form patterned semiconductive tin oxide films (112). The silver salt has also been used in the preparation of ceramic superconductors (113). Neodecanoate salts of barium, copper, yttrium, and europium have been used to prepare superconducting films and patterned thin-fHm superconductors. To prepare these materials, the metal salts are deposited on a substrate, then decomposed by heat to give the thin film (114—116) or by a focused beam (electron, ion, or laser) to give the patterned thin film (117,118). The resulting films exhibit superconductivity above Hquid nitrogen temperatures. 

The submitters report obtaining the product in 99% yield. The enantiomeric excess of the Mosher ester of 3 was measured to be 98% using a Chiralcel OD column (40% 2-propanol/hexane). This optical purity measurement substantiated the optical purity assessment made by 111 NMR studies of 3 and racemic 3 prepared using a different method3. Addition of the chiral shift reagent tris[3-(heptafluoropropylhydroxymethylene)-(+)-camphorato]europium (III) resulted in clear resolution of the respective aromatic proton signals for the two enantiomers, which was demonstrated with the racemate. Under similar conditions, NMR analysis of 3 showed that within the detectable limits of the experiment (ca. <3%), there was none of the disfavored enantiomer. 

All the rare earth metals except samarium, europium, and ytterbium can be prepared in a pure form by reducing their trifluorides with calcium. Magnesium fluoride is less stable than the rare earth fluorides and so magnesium does not figure as a reductant. Lithium forms a fluoride which is stabler than some of the rare earth fluorides and thus finds some use as a reductant. 

Europium oxide (EU2O3) nanorods have been prepared by the sonication of an aqueous solution of europium nitrate in the presence of ammonia. In this reaction, ammonium ions adsorbed on the Eu(OH)3 particles (formed due to the collapse of the bubbles) results in the formation of a monolayer which then fuse together by hydrogen bonding leading to the formation of nanorods [28]. 

Y203 Eu nanoparticles for potential use in FEDs have been prepared in nonionic reverse microemulsions.124 The particles were synthesized by the reaction between aqueous yttrium nitrate, europium nitrate, and ammonium hydroxide, by bulk precipitation in the reverse microemulsion... 

Lanthanide-doped inverse photonic crystals have been reported.282 The lattices were prepared by infilling self-assembled polystyrene sphere templates with a mixture of zirconium alkoxide and europium at 450 °C, the polystyrene spheres were burnt out leaving hollow spheres of air, and the infilled material was converted to Zr02 Eu3+. The PL properties of the resulting photonic lattice were reported.282 The possibility of including phosphors into photonic lattices could lead to many... 

The purest grade of europium metal available from the Lindsay Chemical Division of American Potash is 99.9% Eu in terms of rare earth content, but it may contain up to 1% of other metal impurities (mainly tantalum when prepared in tantalum vessels) and typically contains 2.8 mol % oxygen.6... 

Rare-earth elements have been largely used in these studies. Among them, europium (III) was considered owing to its unusual electronic structure. Eu3+-ion-modified TiOz samples were prepared by a chemical coprecipitation-peptization method [156], which consists of prehydrolysis of TiCl4 by frozen distilled water. The Eu203 powder was added to the above solution to produce a transparent aqueous solution according to the required Eu3+ modifying content (Eu3+ ion equivalent to 3.0 at% of Ti in bulk solution). 

Huhtinen P, Kivela M, Soukka T, Tenhu H, Lovgren T, Harma H (2008) Preparation, characterisation and application of europium(III) chelate-dyed polystyrene-acrylic acid nanoparticle labels. Anal Chim Acta 630 211-216... 

Tan M, Ye Z, Wang G, Yuan J (2004) Preparation and time-resolved fluorometric application of luminescent europium nanoparticles. Chem Mater 16 2494—2498... 

Wu J, Ye Z, Wang G, Jin D, Yuan J, Guan Y, Piper J (2009) Visible-light-sensitized highly luminescent europium nanoparticles preparation and application for time-gated luminescence bioimaging. J Mater Chem 19 1258-1264... 

Preparation.—Two new synthetic routes to simple iodo-phosphines have appeared this year. Thus phosphorus tri-iodide (8) is produced in fairly good yield when the iodides of lanthanum, strontium, or europium are treated with the corresponding phosphates.14 Tetraiododiphosphine (9) is formed in 75—80% yield, by the reaction... 

FIGURE 5. Proton NMR spectra of solutions prepared from (S)-a-phenylethylamine [(S)-22] (10 pL) (upper spectrum) and a mixture of (R)- and (S)-a-phenylethylamine (R)- and (S)-22] (7 and 5 J-L, respectively) (lower spectrum) in 0.3 mL of a carbon tetrachloride solution of tris[3-(ferf-butylhydroxymethylene)-(i-camphorato]europium(III) (96). The chemical shift scale applies only to the lower spectrum. Reprinted with permission from Reference 82. Copyright (1970) American Chemical Society... 

Similar to chemical vapor deposition, reactants or precursors for chemical vapor synthesis are volatile metal-organics, carbonyls, hydrides, chlorides, etc. delivered to the hot-wall reactor as a vapor. A typical laboratory reactor consists of a precursor delivery system, a reaction zone, a particle collector, and a pumping system. Modification of the precursor delivery system and the reaction zone allows synthesis of pure oxide, doped oxide, or multi-component nanoparticles. For example, copper nanoparticles can be prepared from copper acetylacetone complexes [70], while europium doped yttiria can be obtained from their organometallic precursors [71]. 

Europeum metal is prepared from the europium sesquioxide obtained above by the reduction with lanthanum or cerium. The oxide is heated under a vacuum in a tantalum crucible with excess lanthanum turning. Europeum volatilizes and collects as a bright crystalline condensate on the wall of the crucible. It is stored and handled in an inert atmosphere, as the finely divided metal is flammable. 

The reduction to the divalent state involves samarium, europium, and ytterbium. In 1906 C. Matignon and E. Gazes obtained samarium(II) chloride by reducing the trichloride with hydrogen. In 1911, G. Urbain and F. Bourion prepared europium(II) chloride by a comparable reduction involving gydrogen, and in 1929 ytterbium(II) chloride was similarly obtained by W. Klemm and W. Schuth. 

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