Europium nitrate

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... 

An examination of the temperature dependence of the fluorescent lifetime of both terbium nitrate and europium nitrate in methanol and deuterated methanol was made. There was little change with temperature for either. 

Oxides. Industrially, the most important of this group is Y203 Eu3 +. The preparation is generally carried out by precipitating mixed oxalates from purified solutions of yttrium and europium nitrates. Firing the dried oxalates at ca. 600 °C is followed by crystallization firing at 1400-1500 °C for several hours [5.382],... 

Extraction of thorium nitrate and europium nitrate 0 0 4 M) from 1 M HN03 into dichloromethane was carried out for 19 calixarenes totally or partially substituted on the lower rim by phosphine oxide moieties (CPol-CPol7-CPol9-CPo20) and for one calixarene substituted by phosphinate (CP0I8) (see Section 4.7).IM 152 154... 

CJ. Hartzell et al., Molecular modeling of the tributyl phosphate complex of europium nitrate in the clay hectorite. J. Phys. Chem. A 102, 6722-6729 (1998)... 

Hartzell CJ, Cygan RT, Nagy KJ (1998) Molecular Modeling of the Tributyl Phosphate Complex of Europium Nitrate in the ( lay Hectorite, J Phys Chem A 102(34) 6722-6729... 

Question 4.9 Expiain why europium nitrate forms a 1 1 complex [Eu(terpy)(N03)3(H20)] but europium perchlorate forms a 3 1 complex [Eu(terpy)3](C104)3. 

The tetradentate quaterpyridine and hexadentate sexipyri-dine ligands form 1 1 complexes with yttrium aud europium nitrates, respectively the first-named ligand generates nine-coordinate [Y(qtpy)(N03)2(H20)]+ cations while the latter produces 10-coordinate [Eu(spy)(N03)2] cations where the ligand twists itself helically round the metal. ... 

One group was used for spin-on deposition of europium-containing sol prepared from aqueous-alcoholic solution of Ti(OC2Hs)4 precursor and europium nitrate [5]. Then the sample was subjected to heat treatment at 200°C for 30 min... 

For the second group of samples the photoresist was removed (Fig. le) and the samples were anodized in the electrolyte of orthophosphoric acid (Fig. 1 f). Then europium was introduced in the pores of the anodic alumina by immersion of specimen in alcoholic solution of europium nitrate [6]. The specimens were immersed for 2 days and, after removal, subjected to heat treatment within the temperature range of200-500 °C for 30 min (Fig. Ig). 

Figure 3. PL spectra measured from dichromatic luminescent image (a) blue area of porous anodic alumina film of 30 pm thickness after anodizing in oxalic acid electrolyte (b) red area of a porous anodic alumina film of 20 pm thickness after anodizing in orthophosphoric acid electrolyte, followed by immersion in europium nitrate and subsequent heat treatment at 200 °C for 30 min.

The synthesis of the rare-earth oxides was as follows europium oxide was dissolved in a minimum amount of nitric acid and evaporated to dryness. The dry nitrate was dissolved in 5 mL of water. The required amount of silica microspheres was put in a beaker with 30 mL of water and the europium nitrate solution was added. The sonication was carried out for 1 h in an open beaker kept in an ice bath. 5 mL of 25% aqueous ammonia was added dropwise during the sonication. The resulting product after sonication was washed extensively with water, centrifuged, and dried under vacuum. 

The preparation of the europium oxide-doped silica nano-particles (99.0S1O2-I.OEU2O3 mol%) was different. It was also carried out by the hydrolysis of tetraethyl orthosilicate (TEOS) in the presence of H2O, ethanol, and a europium nitrate solution. 25% aqueous ammonia was added dropwise during the sonication. In this way, europium oxide incorporated into silica particles was obtained. 

This series of experiments was continued and we recently deposited sonochemi-cally a nanolayer of EU2O3 on submicron-size titania [84]. Ultrasound irradiation of a slurry of titania, europium nitrate, and ammonia in an aqueous medium for 120 min yielded an Eu203-Ti02 nanocomposite. 

A determination of the stability constants of aquo-complexes of Eu " in acetone showed that as the concentration of water in the solution of europium nitrate in acetone was increased, the first co-ordination sphere of europium(iii) became occupied by three water molecules which replaced three acetone molecules, and only then did the replacement of NO3 anions by water occur. An n.m.r. study of the hydration of lutetium(iii) nitrate in aqueous acetone showed the co-ordination number of lutetium to tend to six with increasing water concentration. The coexistence of several aquo(methyl sulphoxide)lutetium(iii) complexes were identified in the study of the complex formation between lutetium and dimethyl sulphoxide in acetone. 

A NEW BRIGHT CHEMILUMINESCENT REACTION INTERACTION OF ACETONE WITH SOLID-PHASE POTASSIUM MONOPEROXYSULFATE IN THE COMPLEX OF EUROPIUM NITRATE... 

Furthermore, NMR analysis, taken after the CL reaction (injection experiment with KHS05/Eu(N03)3 powders) revealed the presence of acetone and methyl acetate - a product of dimethyldioxirane rearrangement. Methylacetate and acetone were not evaporated at 90 °C because they were bound in a complex with europium so that interaction of acetone with KHSOs takes place in the metal coordination sphere. However, considering involvement of the intermediary dioxirane we cannot exclude the alternative pathway b of Scheme 2, in which europium nitrate may be excited by... 

Studies of Equilibria, Reactions, and Solvent Effects.—Lanthanide shift reagents have been found to be effective for phosphines and phosphoryl compounds, but not for thiophosphoryl compounds. - In a comparison of various shift reagents, europium nitrate hexadeuterium oxide (26) was found to give large shifts of 8 for phosphates and phosphonates. A contact contribution to the Sp shifts was established. When there are two possible sites for co-ordination, as in the aminophosphine (27), steric effects play an important role. Co-ordination occurs at nitrogen in (27 R = H) but at phosphorus in (27 R = Me). The n.m.r. parameters... 

Lu203 Eu (1 at. %) nanopowders were obtained by co-precipitation technique using ammonium hydrocarbonate NH4HCO3 (purity >99.5 %) as a precipitant. Aqueous lutetium and europium nitrate solution was prepared by dissolving of corresponding oxides (purity 99.99 %) in the nitric acid. The precursor precipitate was produced by adding a mother solution to ammonium... 

Ultrasound and microwave irradiation processes are known as excellent methods for the preparation of nanoparticles. Recently, nanoparticles of rare earth (Y, La, Ce, Sm, Eu, and Er) oxides have been synthesized [77-81]. In these cases, rare earth nitrates were used as starting materials. When sodium dodecyl sulfate (SDS) was added as a templating agent, layered and hexagonal mesostructures of high specific surface area (225-250 m g ) can be obtained [77]. Monodispersed Ce02 nanoparticles with a mean particle of ca. 3 nm are obtained when tetrametylammonium hydroxide [78] or polyethylene glycol [79, 80] are used as the additives. In addtion, europium oxide nanorods are obtained by the sonication of an aqueous solution of europium nitrate in the presence of anunonia [81]. The particle sizes were about 50 x 500 nm (IF x L) as described in Fig. 6-9. 

Metal-ion uptake In order to determine the performance of the resins as cation exchangers a resin equivalent to 0.1 meq of acid capacity is shaken with 20 mL of the appropriate metal 10 N ion solution in nitric acid for 24 h and the metal concentration is determined using the atomic absorption method with wavelength set at 213.9, 228.8, 232.9 and 324.8 nm for Zn(II), Cdai), Ni(II) and Cu(II), respectively. The affinity of the resins towards Eu(III) is determined by contacting a resin equivalent to 0.1 mmol of phosphorus with lOmL of 3T0 N europium nitrate solutions in nitrie aeid. The final metal concentration is measured using emission atomie speetroscopy with a wavelength of 459.4 nm. For the result see [114]. 

Europium-doped yttria particles were synthesized by Lee et al. [289] from a two-microemulsion system in which aqueous solutions of yttrium nitrate hexahydrate/europium nitrate hexahydrate or ammonium hydroxide constituted the water phase, a 2 1 (wt ratio) mixture of NP-5 and NP-9 was used as the surfactant and cyclohexane was the continuous phase. The two microemulsions were mixed together with 2 hours stirring at 30 C and the microemulsion was broken by addition of acetone. The mixed hydroxide precipitates were washed with acetone... 

Another investigation of Lee et al. [290] used the same two-microemulsion technique for the preparation of Eu Y203 particles, i.e. mixing of two microemulsions containing NP-5/NP-9 surfactants (20 wt%), cyclohexane (62 wt%) and aqueous solution (18%) of either (i) yttrium and europium nitrate hydrates or (ii) ammonia. The products gathered after breaking of the mixed microemulsions were calcined at 900°C to obtain nanoparticles (spherical, 20-30 nm agglomerates). The steps therefore are ... 

The same surfactant pair (NP-5/NP-9) was also used by Huang et al. [291] for the synthesis of Eu Y203 the continuous phase was petroleum ether. The aqueous phase was a solution of yttrium and europium nitrate, or ammonium hydroxide (as above). The particles of high crystallinity had a size range of 10-100 nm. 

Haile JM (1997) Molecular E namics Simulation Elementary Methods. John Wiley and Sons, New York Hartzell CJ, Cygan RT, Nagy KL (1998) Molecular modeUng of the tributyl phosphate complex of europium nitrate in the clay hectorite. J Phys Chem A 102 6722-6729 Hass KC, Schneider WF, Curioni A, Andreoni W (1998) The chemistry of water on alumina surfaces Reaction dynamics from first principles. Science 282 265-268 Hazen RH (1976) Effects of temperature and pressiue on the cell dimension and X-ray temperature factors of periclase. Am Mineral 61 266-271... 

The interaction between and NOj" ions in aqueous solutions has been studied by several techniques during the past 20 years. A literature survey up to the early 1970s is presented in Gmdin (1974). The main question that has been debated concerns the nature of the complexation is it inner or outer sphere From thermodynamic considerations, Choppin (1971) arrived at a predominantly outer-sphere model see also Choppin and Bertha, 1973. However, in a recent study of fluorescence spectra and lifetimes, Biinzli and Yersin (1979) suggested inner-sphere complexation for europium nitrate, in contrast to the corresponding perchlorate system, see fig. 70. After studying the effect of various ligands on the " Fq transition. 

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