The Low-Temperature Structural Behavior of Sodium 1-Carba-closo-decaborate: NaCB9H10

Published

August 21, 2016

Author(s)

Hui Wu, Wan Si NMN Tang, Wei Zhou, Jacob Daniel Tarver, Vitalie Stavila, Craig Brown, Terrence J. Udovic

Abstract

Two ordered phases of the novel solid superionic conductor sodium 1-carba-closo-decaborate (NaCB₉H₁₀) were identified via synchrotron x-ray powder diffraction in combination with first-principles calculations and neutron vibrational spectroscopy. A monoclinic packing of the large ellipsoidal CB₉H₁₀ anions prevails at the lowest temperatures, but a first-order transformation to a slightly modified orthorhombic packing is largely completely by 240 K. The CB₉H₁₀ anion orientational alignments and Na⁺ cation interstitial sitings in both phases are arranged so as to minimize the cation proximities to the uniquely more positive C-bonded H atoms of the anions. These results provide valuable structural information pertinent to understanding the relatively low-temperature, entropy-driven, order-disorder phase transition for this compound.

Citation

Journal of Solid State Chemistry

Volume

243

Pub Type

Journals

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Keywords

density functional theory, diffraction, ionic conductors, monocarba-closo-decaborates, neutron vibrational spectroscopy, phase transition, phonon density of states, sodium borohydrides

Citation

Wu, H. , Tang, W. , Zhou, W. , Tarver, J. , Stavila, V. , Brown, C. and Udovic, T. (2016), The Low-Temperature Structural Behavior of Sodium 1-Carba-closo-decaborate: NaCB₉H₁₀, Journal of Solid State Chemistry, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=921355 (Accessed December 12, 2024)