%0 Journal Article
%A Hernandez, Olivier
J.
%A Geneste, Gregory
%A Yajima, Takeshi
%A Kobayashi, Yoji
%A Okura, Masatoshi
%A Aidzu, Kouhei
%A Tassel, Cédric
%A Paofai, Serge
%A Swain, Diptikanta
%A Ritter, Clemens
%A Kageyama, Hiroshi
%D 2018
%T Site Selectivity of Hydride in Early-Transition-Metal
Ruddlesden–Popper Oxyhydrides
%U https://acs.figshare.com/articles/journal_contribution/Site_Selectivity_of_Hydride_in_Early-Transition-Metal_Ruddlesden_Popper_Oxyhydrides/6974201
%R 10.1021/acs.inorgchem.8b01645.s001
%2 https://acs.figshare.com/ndownloader/files/12794234
%K VO
%K hydride anions
%K topochemical CaH 2 reduction
%K Sr 3 Ti 2 O 6.875 H 0.125 model system
%K apical site
%K neutron diffraction data refinements
%K B-site chemical nature
%K DFT
%K double-layered Sr 3 Ti 2 O 6.20 H 0.12 material show
%K hydride site selectivity
%K model system Sr 2 TiO 3.875 H 0.125
%X Layered perovskite titanium oxyhydrides
have been prepared by low-temperature
topochemical CaH2 reduction from Ruddlesden–Popper
Srn+1TinO3n+1 phases (n = 1, 2) and
structurally characterized by combined synchrotron X-ray and neutron
diffraction data refinements. In the single-layered Sr2TiO3.91(2)D0.14(1) material, hydride anions
are statistically disordered with oxides on the apical site only,
as opposed to known transition-metal oxyhydrides exhibiting a preferred
occupation of the equatorial site. This unprecedented site selectivity
of H– has been reproduced by periodic DFT+U calculations, emphasizing for the hydride defect a difference
in formation energy of 0.24 eV between equatorial and apical sites.
In terms of electronic structure, the model system Sr2TiO3.875H0.125 is found to be slightly metallic and
the released electron remains mostly delocalized over several Ti atoms.
On the other hand, hydride anions in the double-layered Sr3Ti2O6.20H0.12 material show a clear
preference for the bridging apical site within the perovskite slabs,
as confirmed by DFT calculations on the Sr3Ti2O6.875H0.125 model system. Finally, the influence
of the B-site chemical nature on the hydride site selectivity for
early 3d transition metals is theoretically explored in the single-layered
system by substituting vanadium for titanium. The V3+ electronic
polaron is suggested to play a role in stabilizing H– on the equatorial site in Sr2VO4–xHx for x = 0.125.
%I ACS Publications