[en] Reports of studies carried out on the inorganic coordination chemistry of vanadium are reviewed. 167 refs.; 25 figs

[en] A selective and quantitative extraction procedure for vanadium(IV), as a adipate complex, with Adogen-464[methyltri(C₈-C₁₀)alkylammonium chloride, mol.wt. 431] dissolved in chloroform is described. The method was optimized from the study of the effects of different parameters on the extraction efficiency and was subsequently applied to the determi-nation of vanadium in several complex matrices. (author). 19 refs.; 1 fig.; 2 tabs

[en] The blue vanadium(IV) compound VO(HPO₄)·O.5H₂O has been identified as precursor to the maleic anhydride catalyst (VO)₂P₂O₇. Structural similarities between the two compounds suggest a topotactic transformation from hydrogen phosphate to pyrophosphate as the mechanism of catalyst activation. In both compounds, measurement of the magnetic susceptibility as a function of temperature reveals that the major bulk fraction of the vanadium spins are antiferromagnetically coupled, while a variable minor fraction of the defect spins are nearly isolated from the other spins. Two new phases of VOPO₄ are formed upon oxidation of VO(HPO₄)·O.5H₂O. 19 refs.; 5 figs.; 3 tabs

[en] We systematically search for the stable structures of two-dimensional (2D) V-V binary compounds with honeycomb-like structure by using the first-principles calculation. We identify 26 stable structures out of 54 2D V-V compounds based on various assessments of stabilities: total energy, thermodynamics, and mechanics. Among them, 12 2D V-V compounds are previously unrecognized structures. For each class V-V isomer, the most stable structures are found to be β-AsP, β-SbAs, α-BiAs, α-BiSb, α ₂-SbP, and α ₂-BiP. For all isomers of the AsP, they are always stable, and hence PAs monolayer is most likely to be prepared experimentally. All the stable structures are semiconductors with bandgaps ranging from 0.06 eV to 2.52 eV at the Heyd–Scuseria–Ernzerhof level. Therefore, they are potential materials for versatile semiconductor devices. Our findings provide a new clue to facilitate the design of 2D materials for potential applications. (paper)

No abstract available

No abstract available

[en] The results of a study on the chemistry of the precipitation process of vanadium compounds in sulfuric media are presented, in order to recover the vanadium contained in the ore from Campo Alegre de Lourdes (Bahia-Brazil). (Author)

No abstract available

No abstract available

[en] Influence of copper (2) ions on interaction of vanadium with 2,4-dithiobiuret in weakly acidic media is studied. Preliminary reduction of copper up to the univalent one which later on reduces vanadium (5) is the most probable under given conditions