12159-20-5Relevant articles and documents
Isotope effects in the kinetics of simultaneous H and D thermal desorption from Pd
Leardini,Fernández,Bodega,Sánchez
, p. 116 - 127 (2008)
The kinetics of simultaneous hydrogen and deuterium thermal desorption from PdHxDy has been investigated. A novel experimental approach for the study of the transition state (TS) characteristics of the surface recombination reaction is proposed based on the analysis of the H and D partitioning into H2, HD and D2 molecules. It has been found that the hydrogen molecular isotopes distribution is determined by the energy differences of the corresponding TS of the atom-atom recombination reactions. On the other hand, the mechanisms and activation energies of the desorption process have been obtained. At 420 K, the desorption reaction changes from a surface recombination limiting mechanism during desorption from β-PdHxDy to a reaction limited by the rate of β to α phase transformation during the two phase coexistence. Surface recombination reaction becomes again rate limiting above 480 K, due to a change in the catalytic properties of the Pd surface. TS energies obtained from the kinetic analysis of the thermal desorption spectra are in good accordance with those obtained from the analysis of the H2, HD and D2 distributions. Anomalous TS energies have been observed for the H-D recombination reaction, which may be related to the heteronuclear character of this molecule.
Low temperature investigation of hydrogen bridge bonds in lithium tetrahydroxoborate by Raman spectroscopy, X-ray and neutron diffraction (Li 11B(OD)4)
Jacobs, Herbert,Niemann, Anke,Kockelmann, Winfried
, p. 871 - 875 (2006)
Low temperature Raman spectroscopic measurements on isotopically diluted Li11B(OH)4 with 8% D and Li11B(OD)4 with 8% H reveal four crystallographically different hydrogen bridge bonds. With decreasing temperatures beginning at ～50 K measured down to ～10 K the stretching modes of the hydroxide ions shift to higher wave numbers. For the strongest bond O-D...O the frequency shift is 16 cm-1 and for the weakest 7 cm-1. For O-H...O the maximum in the frequency shift is 22 cm-1. X-ray single crystal (LiB(OH)4) and neutron powder diffraction (Li11B(OD)4) data result in bond lengths for the four hydroxide ions in the range of 0.943 (3) A ≤ d(O-D) ≤ 0.974 (3) A. The value of the effect of inversion of the stretching mode frequencies seems to correlate with the strength of the hydrogen bridge bonds and is found to be different for the two isotopes H and D in this compound.
Complexing Lithium Salts and Lithium Oxide or Hydroxide: Synthesis and Characterization of a New Cation - Lithiumhydroxonium Li2OH(+)
Nikitina, Z. K.,Nikitina, N. I.,Rosolovskii, V. Ya.
, p. 1295 - 1298 (2008/10/08)
An atempt is made to prepare salts of Li2OH(+) and Li3O(+) belonging to the series of simplest oxonium cations H3O(+), LiOH2(+), Li2OH(+) and Li3O(+), whwre the proton and lithium replace each other. Double compoundsof lithium hydroxide with lithium chloride and perchlorate have been ob tained: LiOH * LiClO4, LiOD * LiClO4, LiOH * LiCl, LiOD * LiCl, and LiClO4 * 2LiCl. IR absorption spetra suggest that the perchlorate adduct canbe built of ClO4(-) anions and [Li2OH](+) complex cations. In the chlor ide adduct, OH(-) and Cl(-) regularly alternate in the crystal lattice, and, thus, two types of anion polyhedra surrounding lithium cations overlap. No interaction of Li2O with LiClO4 or LiCl occurs under the conditions of our experiments.
