Molybdenum, structure determination

Molybdenum and Tungsten Bronzes.—The results of the majority of studies of studies of new bronze phases are summarized in Table 9. Sno.2W03 and Sno.3 WO3 have been prepared and their crystal structures determined. Whether they are bronzes is debatable since they do not involve a host lattice of WO ... 

SiMouO ]4-.134 The structure of the heteropoly blue species (four-electron-reduced PM012O40]3-) formed in the molybdenum blue determination of phosphorus has been reported135 and a review of molybdate heteropoly blues has appeared.130 A stability index of polyanion structures has been discussed.137 The presence of two PMo, anions in aqueous solutions of molybdate and phosphate has been demonstrated by 31P NMR.138 Solid state NMR (nonspinning and MAS techniques) has been used for characterization of heteropolyanions.139 Molybdenum-95 NMR spectra of some polymolybdates have been reported.140... 

Oxo complexes dominate the chemistry of molybdenum in its higher oxidation states,5 80,92 93 and play a major role in the catalytic activity of molybdenum in biological systems (see Section 36.6.7). MoIV complexes have been characterized containing the monooxo (MoO 2+ and the trans-dioxomolybdenum(IV) Mo02 cores, but no compound has been isolated analogous to the ds-dioxomolybdenum(VI) species described in Section 36.5. Crystal structure determinations have been accomplished for a number of MoIV complexes, and some typical examples are listed in Table 3.80... 

A crystal structure determination of [pyH]4[Mo203(S04)(NCS)6] has shown the two molybdenum atoms to be bridged by one oxo and the sulfato ligand. The terminal oxygens are syn and each molybdenum has a distorted octahedral geometry.415 Persulfide bridges have been identified in several dimeric Mov complexes. In each molybdenum is... 

A series of polyether macrocycles (40)-(47) that contain a coordinated reducible transition metal redox-active 16-electron molybdenum nitro-syl Mo(NO) 3+ group have been prepared by us in collaboration with McCleverty and Jones (86,87) (Scheme 14). Compounds (40)-(44) were synthesized from the reactions between [Mo(NO)LX2] (L = tris(3,5-dimethylpyrazolyl)hydroborate X = Cl or I) and the appropriate amine-substituted benzo crown ether. Compounds (45)—(47) were prepared from reactions between [Mo(NO)LI2] and tetra-, penta-, or hexa-ethylene glycol, respectively, in the presence of triethylamine. A crystal structure determination of (45) (88) is shown in Fig. 14. 

The structure consists of a tetrahedral arrangement of sulfur atoms around each molybdenum and copper atom, with each tetrahedron sharing two comers with each of its two neighbors. The ammonium Ions are located in the spaces between the chains. The Mo-S distance is 2.19 A in accord with those found in (NH4)2MoS4193. A structure determination has been carried out also on pipera-zinium tetrathiomolybdate, (C4H12N2)MoS4195. The MoS42 anion is tetrahedral with Mo-S distances 2.18 A, and the piperazinium ion is in the chair form. 

X-Ray Crystal Structure Determinations of Molybdenum(II) and Tungsten(II) Halocarbonyl Alkyne Complexes Reported since 1987... 

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