Interplay between the Reorientational Dynamics of the B3H8- Anion and the Structure in KB3H8
Journal article, 2021

The structure and reorientational dynamics of KB3H8 were studied by using quasielastic and inelastic neutron scattering, Raman spectroscopy, first-principles calculations, differential scanning calorimetry, and in situ synchrotron radiation powder X-ray diffraction. The results reveal the existence of a previously unknown polymorph in between the alpha'- and beta-polymorphs. Furthermore, it was found that the [B3H8](-) anion undergoes different reorientational motions in the three polymorphs alpha, alpha', and beta. In alpha-KB3H8, the [B3H8](-) anion performs 3-fold rotations in the plane created by the three boron atoms, which changes to a 2-fold rotation around the C-2 symmetry axis of the [B3H8](-) anion upon transitioning to alpha'-KB3H8. After transitioning to beta-KB3H8, the [B3H8](-) anion performs 4-fold rotations in the plane created by the three boron atoms, which indicates that the local structure of beta-KB3H8 deviates from the global cubic NaCl-type structure. The results also indicate that the high reorientational mobility of the [B3H8](-) anion facilitates the K+ cation conductivity, since the 2-orders-of-magnitude increase in the anion reorientational mobility observed between 297 and 311 K coincides with a large increase in K+ conductivity.

Author

Mikael Andersson

National Institute of Standards and Technology (NIST)

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry 2

J. B. Grinderslev

Aarhus University

X-M Chen

Henan Normal University

X. Chen

Zhengzhou University

Henan Normal University

U. Haussermann

Stockholm University

Wei Zhou

National Institute of Standards and Technology (NIST)

T. R. Jensen

Aarhus University

Maths Karlsson

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry 2

T. J. Udovic

University of Maryland

National Institute of Standards and Technology (NIST)

Journal of Physical Chemistry C

1932-7447 (ISSN) 1932-7455 (eISSN)

Vol. 125 7 3716-3724

Surface/interface dynamics investigated with neutron scattering

Swedish Research Council (VR), 2017-01-01 -- 2020-12-31.

Subject Categories

Inorganic Chemistry

Materials Chemistry

Structural Biology

DOI

10.1021/acs.jpcc.0c10186

More information

Latest update

4/9/2021 1