Europium metals with

Eu—G system.—The black dicarbide, EuC2, was prepared by GEBELTand Eick [231] by the reaction of europium metal with graphite (1 2 ratio) in a steel bomb at about 1050° G. The compound has a body-centered tetragonal structure with the lattice parameters a = 4.045 and c 6.645 A. The lattice constants compare reasonably well with SrC2 (a = 4.11, c = 6.68 A). 

Reductive methods may be employed to prepare lower fluorides. For example, treatment of europium metal with even the mildest fluorinating... 

At one extreme, a derivative free of coordination by water or anions has been prepared by the reaction of europium metal with NOBF4 in dry acetonitrile (Albin et al., 1983). The resulting Eu(CH3CN) (Y) species (Y = BF4, PF ) reacts further with two equivalent ionophoric ligands to give bis(ligand) complexes. 

C19-0019. A cell is constructed with europium metal and a 1.00 M solution of E11CI2 in one... 

Exposure of naphthalene dissolved in liquid ammonia to europium metal immediately results in the characteristic green color of naphthalene anion-radical. ESR analysis reveals a signal that comes from an unpaired electron interacting with Eu and Eu nuclei. No hyperfine coupling with naphthalene protons is observed, although treatment with water leads to 1,4-dihydronaphthalene (Stevenson et al. 1999). This means that naphthalene has indeed been reduced to its anion-radical and undergone a normal Birch reaction. These results are consistent with the initial donation of two... 

Bender JL, Corbin PS, Fraser CL, Metcalf DH, Richardson FS, Thomas IiL, Urbas AM. Site-isolated luminescent europium complexes with polyester macroUgands metal-centered heteroarm stars and nanoscale assemblies with labile block junctions. J Am Chem Soc 2002 124 8526-8527. 

It has now become apparent that f-band superconductors can be understood in a normal way, like d-band ones" we have just to think about density of states, bandwidth lattice unstabilities and electron correlations to interpret it. This was clearly summarized by Smith after the discovery of superconductivity of Pa and Am. Superconductivity of Am is made by the J = 0 ground state of its six 5 f electrons as was stressed by Johansson , this could also be the case for stabilized trivalent europium metal. The importance of lattice instabilities (like in A-15 high Tc superconductors) was put forward by Fournier who showed that the very large 6T/8p slope for U was mainly due to a very targe change in the electron-phonon coupling associated with the low temperature phase transition. 

Results of Reactions Designed to Produce Ternary Hydrides of Some Rarer Platinum Metals with Europium or Ytterbium... 

EvO. — This lower oxide of europium was prepared by the reduction of EuaOs with lanthanum metal at 1300 —1500° C by Eick et al. [319]. EuO has a NaCl type structure with a = 5.1439 0.0005 A. Gaston and Hukln [320] attempted the preparation of EuO by controlled oxidation of europium metal at 350° C with a stoichiometric addition of oxygen and obtained the oxide in fairly pure state. They also tried the thermal decomposition of EuCOs, Eu(HCOO)2 and Eu(OH)2. Only Eu(OH)2 proved to be advantegeous and gave a sample of EuO of reasonable purity. 

Calix[ ]arenes are a family of macrocycles prepared by condensation reactions between n /v/ra-substituted phenols and n formaldehyde molecules under either base or acid catalysis. Different sizes of the macrocycles can be obtained (n = 4-20) (Stewart and Gutsche, 1999) depending on the exact experimental conditions, which were mastered in the 1960 s (Gutsche, 1998), but the most common receptors are those with n =4,6,8 (macrocycles with an odd number of phenol units are more difficult to synthesize). We use here the simplified nomenclature in which the number of phenolic units is indicated between square brackets and para substituents are listed first.4 Calixarenes, which can be easily derivatized both on the para positions of the phenolic units and on the hydroxyl groups, have been primarily developed for catalytic processes and as biomimics, but it was soon realized that they can also easily encapsulate metal ions and the first complexes with d-transition metal ions were isolated in the mid-1980 s (Olmstead et al., 1985). Jack Harrowfield characterized the first lanthanide complex with a calixarene in 1987, a bimetallic europium complex with p-terf-butylcalix[8]arene (Furphy etal., 1987). 

R.O. Moyer Jr, R. Lindsay D.N. Marks (1978). In Transition metal Hydrides, ed. R. Bau, Advances in Chemistry Series 167, American Chemical Society, Washington D.C., pp 366-38. Results of reactions designed to produce ternary hydrides of some rarer platinum metals with europium or ytterbium. 

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