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Title: Structures and Properties of the Products of the Reaction of Lanthanide Atoms with H 2 O: Dominance of the +II Oxidation State

We studied, lanthanides and H2O reactions using density functional theory with the B3LYP functional. H2O forms an initial Lewis acid-base complex with the lanthanides exothermically with interaction energies from -2 to -20 kcal/mol. For most of the Ln, formation of HLnOH is more exothermic than formation of H2LnO, HLnO + H, and LnOH + H. Moreover, the reactions to produce HLnOH are exothermic from -25 to -75 kcal/mol. The formation of LnO + H2 for La and Ce is slightly more exothermic than formation of HLnOH and is less or equally exothermic for the rest of the lanthanides. The Ln in HLnOH and LnOH are in the formal +II and +I oxidation states, respectively. The Ln in H2LnO is mostly in the +III formal oxidation state with either Ln-O-/Ln-H- or Ln-(H2)-/Ln= O2- bonding interactions. A few of the H2LnO have the Ln in the +IV or mixed +III/+IV formal oxidation states with Ln=O2-/Ln-H- bonding interactions. The Ln in HLnO are generally in the +III oxidation state with the exception of Yb in the +II state. The orbital populations calculated within the natural bond orbital (NBO) analysis are consistent with the oxidation states and reaction energies. The more exothermic reactions tomore » produce HLnOH are always associated with more backbonding from the O(H) and H characterized by more population in the 6s and 5d in Ln and the formation of a stronger Ln-O(H) bond. Overall, the calculations are consistent with the experiments in terms of reaction energies and vibrational frequencies.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [4] ;  [1]
  1. Univ. of Alabama, Tuscaloosa, AL (United States)
  2. Univ. of Alabama, Tuscaloosa, AL (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Washington State Univ., Pullman, WA (United States)
  4. Univ. of Virginia, Charlottesville, VA (United States)
Publication Date:
OSTI Identifier:
1261512
Grant/Contract Number:
AC05-00OR22725; FG02-12ER16329; SC0001034
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory
Additional Journal Information:
Journal Volume: 120; Journal Issue: 5; Journal ID: ISSN 1089-5639
Publisher:
American Chemical Society
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY