LiSc(BH₄)₄: A Novel Salt of Li⁺ and Discrete Sc(BH₄)₄⁻ Complex Anions

Abstract

LiSc(BH 4 ) 4 has been prepared by ball milling of LiBH 4 and ScCl 3 . Vibrational spectroscopy indicates the presence of discrete Sc(BH 4 ) 4 -ions. DFT calculations of this isolated complex ion confirm that it is a stable complex, and the calculated vibrational spectra agree well with the experimental ones. The four BH 4 -groups are oriented with a tilted plane of three hydrogen atoms directed to the central Sc ion, resulting in a global 8 + 4 coordination. The crystal structure obtained by high-resolution synchrotron powder diffraction reveals a tetragonal unit cell with a ) 6.076 Å and c ) 12.034 Å (space group P-42c). The local structure of the Sc(BH 4 ) 4 -complex is refined as a distorted form of the theoretical structure. The Li ions are found to be disordered along the z axis.

NaSc(BH4)4: A Novel Scandium-Based Borohydride

“…9 The desorption properties of the same compound were studied recently, showing the release of about 6.4 wt % of the initial hydrogen content at 673 K. 10 This reaction, however, did not show a complete reversibility. Here, we report on the crystal structure; desorption properties; and Raman, infrared, and NMR spectra of another scandium-based bimetallic borohydride, NaSc(BH 4 ) 4 .…”

Synthesis, Crystal Structure, and Thermal Properties of the First Mixed-Metal and Anion-Substituted Rare Earth Borohydride LiCe(BH4)3Cl

“…[Sc(BH 4 ) 4 ] -anion has been observed for the first time in the series of MSc(BH 4 ) 4 (M = Li, Na, K) compounds [5][6][7][8][9] . 5 (M = Li, Na) 9 .…”

“…5 (M = Li, Na) 9 . The structures of the Zn-series feature two doubly-interpenetrated 3D frameworks similar to those found in metal organic frameworks (MOF), and observed for the first time in a metal hydride.…”

“…Among those are the series of Sc-containing MSc(BH 4 ) 4 (M = Li, Na, K) and Zncontaining compounds MZn 2 (BH 4 ) 5 and MZn(BH 4 ) 3 (M = Li, Na).…”

Physical Chemistry at the University of Geneva

“…This research has led to the first structural characterization of several compounds such as the intensively studied magnesium borohydride (Mg(BH 4 ) 2 ), [21] and the complex material LiSc(BH 4 ) 4 . [22] The first experimental data of the elastic constants of NaBH 4 have been obtained using inelastic X-ray scattering and the anharmonic behaviour has been studied using Raman spectroscopy. The current investigations of H. Hagemann and his co-workers aim at the development of isotopically labelled compounds as new structural probes of these materials.…”