USGS · 70221367
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H. T. Evans. 2002-05-01. Refined molecular structure of the heptamolybdate and hexamolybdotellurate ions. https://doi.org/10.1021/ja01014a073
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Spectra of several fluorobenzene cation radicals containing 1-3 methyl substituents were observed in solid Ne matrix and analyzed. Comparisons between these compounds and other fluorobenzenes studied previously as well as comparisons between the Β ~ state lifetimes in the gas phase and in the matrix are used to gain a deeper insight into the Β ~ state decay dynamics.
When solutions of cobalt(II) ion and heptamolybdate ion (Mo₇O₂₄⁶⁻) are mixed in the presence of an oxidizing agent (such as bromine), Kurnakov, Hall, and others found that an emerald green complex is formed as the main product, namely, the heteropoly complex ion hexamolybdocobaltate(III), which forms salts such as (NH₄)₃[H₆CoMo₆O₂₄]·12H₂O. Friedheim and Keller showed that at the same time a small amount of another complex is also formed, having a Co:Mo ratio of 1:5. Tsigdinos, et al., found that if a hot solution of the hexamolybdocobaltate complex ion is treated with activated charcoal or Raney nickel the 1:6 complex is converted almost entirely to the 1:5 complex. These workers proved the latter to be a dimer, and formulated the ammonium salt (earlier prepared by Friedheim and Keller) as (NH₄)₆[Co₂Mo₁₀O₃₆]·10H₂O. We have now completed a crystal structure analysis of this interesting compound, which shows the proper formula to be (NH₄)₆[H₄Co₃Mo₁₀O₃₈]·7H₂O.
The synthesis and properties of 1,2,4,5-tetrafluorobenzene and a group of bromofluoro and chlorofluorobenzenes with a predominating 1,2,4,5-structure are described. Flash point and surface tension data for the fluorinated benzenes and the influence of chlorine substitution upon these values were studied. Under nitration conditions, 1,2,4,5-tetrafluorobenzene will not form a nitro derivative, but will undergo a preferential 1,4-fluorine displacement-oxidation mechanism to give 2,5-difluoro-1,4-benzoquinone. Diazotization reactions on 2-nitro-3,4,6-trifluoroaniline reveal that the nitro group or a fluorine atom in the 4- or 6-position may become labilized, under certain conditions, and undergo replacement.