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Characterization of Distortional Isomers of the Anions Pentacyano-oxo-molybdate(IV) and of Tetracyano-aqua-oxo-molybdate(IV) in the Solid State. Crystal Structures of [(C6H5)4P]3[MoO(CN)5] · 7 H2O (green), [(C6H5)4As]2[MoO(OH2)(CN)4] · 4 H2O (blue), and [(C6H5)4P]2[MoO(OH2) (CN)4] · 4 H2O (green) Preparation of a series of salts containing the new pentacyano-oxo-molybdate(IV) anion is described: Cs2H[MoO(CN)5] (blue), [(CH3)4N]2H[MoO(CN)5] · 2 H2O (blue) and [Cr(en)3] [MoO(CN)5] · 4 H2O (green). The green [(C6H5)4P]3[MoO(CN)5] · 7 H2O crystallizes triclinic in the space group P1 . The molybdenum(IV) center is in an pseudo-octahedral environment of a terminal oxo-group (d(Mo?O); 1.705(4) Å), a CN? group in the trans-position (d(Mo? C): 2.373(6) Å), and four equatorial CN? groups (averaged d(Mo? C): 2.178 (Å). The blue and green salts exhibit v(Mo?O) stretching frequencies at 948 cm?1 and 920 cm?1, respectively. Blue and green salts containing the [MoO(OH2)(CN)4]2? anion and [(C6H5)4P]+ or [(C6H5)4As]+ cations have been prepared and characterized by single crystal crystallography. [(C6H5)4P]2[MoO(OH2)(CN)4] · 4 H2O (green) and [(C6H5)4As]2[MoO(OH2)(CN)4] · 4 H2O (blue) crystallize monoclinic in the space group C—P21/n. They are considered to be distortional isomers of the complex anion: the green species has a Mo?O bond distance of 1.72(2) Å whereas for the blue species d(Mo?O) = 1.60(2) Å is found; the corresponding v(Mo?O) frequencies are at 920 cm?1 and 980 cm?1. 相似文献
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Shashwati Sen DK Aswal Ajay Singh TV Chandrasekhar Rao KP Muthe JC Vyas LC Gupta SK Gupta VC Sahni 《Pramana》2002,58(5-6):867-870
The MgB2 superconductor, synthesized using solid-state and liquid-phase sintering methods, have been characterized for various properties.
The upper critical field, irreversibility line and critical current density have been determined using magnetization data.
The current-voltage characteristics recorded under an applied magnetic field revealed the existence of vortex glass transition.
The surface analysis using X-ray photoelectron spectroscopy shows that MgB2 is sensitive to atmospheric degradation. 相似文献
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Park HS Blewitt G Cortez BG Foster GW Gajewski W Haines TJ Kielczewska D LoSecco JM Bionta RM Bratton CB Casper D Chrysicopoulou P Claus R Errede S Ganezer KS Goldhaber M Jones TW Kropp WR Learned JG Lehmann E Reines F Schultz J Seidel S Shumard E Sinclair D Sobel HW Stone JL Sulak LR Svoboda R van der Velde JC Wuest C 《Physical review letters》1985,54(1):22-25
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Seidel S Bionta RM Blewitt G Bratton CB Casper D Ciocio A Claus R Dye ST Errede S Foster GW Gajewski W Ganezer KS Goldhaber M Haines TJ Jones TW Kielczewska D Kropp WR Learned JG LoSecco JM Matthews J Park HS Price L Reines F Schultz J Shumard E Sinclair D Sobel HW Stone JL Sulak L Svoboda R Thornton G van der Velde JC Wuest C 《Physical review letters》1988,61(22):2522-2525
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