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    Hydrogen Isotope Fractionation in Aqueous Alkaline Earth Chloride Solutions
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    Abstract:
    The D/H ratio of hydrogen gas in equilibrium with aqueous alkaline earth (Mg, Ca, Sr or Ba) chloride solutions measured at 25 ◦ C using a hydrophobic platinum catalyst, was found to be higher than the D/H ratio equilibrated with the applied pure water. The hydrogen isotope effect between such solutions and pure water changes with the molality of the solutions. The order of the D/H ratios in alkaline earth chlorides is found to be BaCl 2 > SrCl 2 ≥ CaCl 2 ≥ MgCl 2 . The hydrogen isotope effect in the aqueous chloride solutions of Mg, Ca, Sr or Ba ions is significantly larger than that in the aqueous chloride solutions of Li, Na, K or Cs ions. For MgCl 2 and CaCl 2 solutions, the hydrogen isotope effect is opposite to the oxygen isotope effect. The results are compared with the free energy change of transfer from H 2 O to D 2 O, and are discussed for the vapour pressure ratio of H 2 O and D 2 O of CaCl 2 solutions.
    Keywords:
    Molality
    Alkaline earth metal
    Kinetic isotope effect
    Hydrogen chloride
    The effects of equal concentrations of the alkali and alkaline earth chlorides and of hydrogen chloride on the absorption spectra of aqueous cobalt chloride solutions have been studied. Solutions prepared both on the molar and on the molal bases were used. In all cases, the absorption bands widen with an increase in concentration of the added salt. The increase in width of the absorption bands varies directly as the ionic charge and inversely as the ionic volume of the added cation. The inadequacy of existing explanations of the well-known color changes in cobalt chloride solutions is discussed and a new explanation is offered.
    Molality
    Citations (2)
    The D/H ratio of hydrogen gas in equilibrium with aqueous alkaline earth (Mg, Ca, Sr or Ba) chloride solutions measured at 25 ◦ C using a hydrophobic platinum catalyst, was found to be higher than the D/H ratio equilibrated with the applied pure water. The hydrogen isotope effect between such solutions and pure water changes with the molality of the solutions. The order of the D/H ratios in alkaline earth chlorides is found to be BaCl 2 > SrCl 2 ≥ CaCl 2 ≥ MgCl 2 . The hydrogen isotope effect in the aqueous chloride solutions of Mg, Ca, Sr or Ba ions is significantly larger than that in the aqueous chloride solutions of Li, Na, K or Cs ions. For MgCl 2 and CaCl 2 solutions, the hydrogen isotope effect is opposite to the oxygen isotope effect. The results are compared with the free energy change of transfer from H 2 O to D 2 O, and are discussed for the vapour pressure ratio of H 2 O and D 2 O of CaCl 2 solutions.
    Molality
    Alkaline earth metal
    Kinetic isotope effect
    Hydrogen chloride
    Citations (6)
    E.s.r. studies have revealed that the radical ion Cl2– is a major product of radiolysis of the title compounds at 77 K. The marked reduction in g⊥ compared with those for VK centres in alkali-metal and alkaline-earth metal halides shows that Cl2–, especially in solid hydrogen chloride, is strongly hydrogen bonded. Hydrogen atoms are formed in good yield in CsHCl2, but not in HCl. However, the hyperfine coupling of 495 G is unusually low and the g-value (2·0050) unusually high. These results, and the linewidths (ca. 17 G), are interpreted in terms of weak bonding to neighbouring chlorine atoms.Of the other magnetic species formed, the most interesting is characterised by a well resolved 109 G doublet obtained from irradiated HCl. This was shown by use of DCl to be due to coupling to a single proton. A similar doublet, having a subsidiary structure consisting of four lines separated by ca. 10 G was partially concealed by the main doublet. After removal of the irradiated HCl, a broad doublet, was again given with a(H)ca. 139 G. It is postulated that these radicals are of the form HSi(OH)2, HSiCl(OH), and HSi(O–)2.The mechanism of radiation damage is discussed.
    Hydrogen chloride
    Caesium
    Alkaline earth metal
    Citations (2)
    The reaction of uranium dioxide with excess hydrogen chloride in alkali chloride melts (LiCl, 3LiCl-2KCl, NaCl-KCl and NaCl-2CsCl) has been studied between 450 and 750 ◦ C, and the reaction products were characterized by electronic absorption and X-ray absorption spectroscopy. Uranium( V), [UO 2 Cl 4 ] 3− , and uranium(IV), [UCl 6 ] 2− , species were formed. They depended upon the temperature and the radius of the alkali cations present. Uranium(V) ions predominated in melts with small cations (LiCl and 3LiCl-2KCl).
    Hydrogen chloride
    Uranium dioxide
    Citations (15)