Synthesis and X-Ray Characterization

As the samples contained a small amount of tetravalent iron, a further annealing under low partial oxygen pressure was necessary in order to reduce FeIV to trivalent iron. Typical conditions were  

X-ray diffraction analysis reveals two different vacancy distributions without the detection of a two-phase domain in every system. For low values of y S 0.25, the symmetry of the perovskite remains which indicates that the vacancies are apparently disordered. At higher values of y = 0.25 X-ray patterns give evidence of a distortion. For y = 0.25, they can be indexed with the theoretical parameters (orthorhombic symmetry) deduced from the vacancy ordering previously described. As a consequence, an order-disorder transition takes place around y 0.25. This phenomenon is illustrated in Fig. 4, which shows a discontinuity of the unit cell volume Vm around this value for each system. 

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G. Ciani, A. Magni, A. Sironi, and S. Martinengo, Synthesis and X-Ray Characterization of the High-nuclearity [Rh17( i3-CO)3( j,-CO)15(CO)12]3 Anion containing a Tetra-capped Twinned Cuboctahedral Cluster, J. Chem. Soc., Chem. Comm. 1981,1280-1281. 

Sessler, J.L. Mody, T.D. Lynch, V. Synthesis and x-ray characterization of a unranyl(VI) Schiff base complex derived from 2 2 condensation product of 3,4-diethylpyr-role-2,5-dicarbaldehyde and l,2-diamino-4,5-dimethoxy-benzene. Inorg. Chem. 1992. 31 (4), 529-531. 

G.K. Ramachandran, J. Dong, J. Dieffenbacher et al.. Synthesis and X-ray characterization of silicon clathrates. Solid State Chem. 145, 716-730 (1999)... 

Briant CE, Theobald BRC, White JW et al (1981) Synthesis and X-ray structural characterization of the centered icosahedral gold cluster compound [Aui3(PPhMe2)ioCl2](PF6)3 the realization of a theoretical prediction. Chem Commun 5 201-202... 

Wang, Z. Reibenspies, J. Martell, A. E. Design, synthesis and X-ray structural characterization of new dinucleating macrocyclic ligands and a novel phenolate-bridged dilanthanum(III) complex. Inorg. Chem. 1997, 36, 629-636. 

S. Martinengo, G. Ciani, and A. Sironi, Synthesis and X-ray Structural Characterization of the [Rh22(F3-CO)7( i-CO)18(CO)12]4 Anion Containing a Large Close-Packed Cluster with an ABAC Sequence of Compact Layers, J. Am. Chem. Soc. 102, 7564-7565 (1980). 

A recent development in the low-valent lanthanide area is the synthesis and X-ray structural determination of the unsolvated complex (C5Me5)2Sm 121). This species is the first structurally characterized bis(cyclopentadienyl)lanthanide species which has no other ligands in the metal coordination sphere. As such, it is the closest lanthanide analogue of the bis(ring)metallocene sandwich compounds like ferrocene. Samarocene was obtained by desolvation of (C5Me5)2Sm(thf)2 under high vacuum and sublimation of the product [Eq. (58)]. The sublimed crystals have a bent... 

Evans, W.J., Meadows, J.H., Wayda, A.L. et al. (1982). Synthesis and X-ray crystallographic characterization of dimeric organolanthanide and organoyttrium hydride complexes. Journal of the American Chemical Society, 104, 2008. 

The synthesis and X-ray crystallographic characterization of a Pd complex 30 with a rigid C,N,C-tridentate pincer carbene ligand was investigated. Suzuki coupling reactions are catalyzed by 30 the reaction is unaffected by air (Equation 58) [74]. 

Bernard, R., Cornu, D., Perrin, M., Schaff, J.-R, and Miele, P. 2004. Synthesis and x-ray structural characterization of the tetramethylene oxonium derivative of the hydrodecaborate anion. A versatile route for derivative chemistry of [BioHiol. 7. Organomel Chem. 689 2581-2585. 

Besides synthesis, current basic research on conducting polymers is concentrated on structural analysis. Structural parameters — e.g. regularity and homogeneity of chain structures, but also chain length — play an important role in our understanding of the properties of such materials. Research on electropolymerized polymers has concentrated on polypyrrole and polythiophene in particular and, more recently, on polyaniline as well, while of the chemically produced materials polyacetylene stih attracts greatest interest. Spectroscopic methods have proved particularly suitable for characterizing structural properties These comprise surface techniques such as XPS, AES or ATR, on the one hand, and the usual methods of structural analysis, such as NMR, ESR and X-ray diffraction techniques, on the other hand. 

Cinellu, M.A., Minghetti, G., Pinna, M.V., Stoccoro, S., Zucca, A., Manassero, M. and Sansoni, M. (1998) X-Oxo and alkoxo complexes of gold(III) with 6-alkyl-2,2 -bipyridines. Synthesis, characterization and X-ray structures. Journal of the Chemical Society,... 

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