Karol J. Fijalkowski, Radostina V. Genova, Yaroslav Filinchuk, Armand Budzianowski, Mariana Derzsi, Tomasz Jaroń, Piotr J. Leszczyński and Wojciech Grochala
We describe the successful synthesis of the first mixed–cation (pseudoternary) amidoborane, Na[Li(NH2BH3)2], with theoretical hydrogen capacity of 11.1 wt%. Na[Li(NH2BH3)2] crystallizes triclinic (P) with a=5.0197(4)Å, b=7.1203(7)Å, c=8.9198(9)Å, α=103.003(6)°, β=102.200(5)°, γ=103.575(5)°, and V=289.98(5)Å3 (Z=2), as additionally confirmed by Density Functional Theory calculations. Its crystal structure is topologically different from those of its orthorhombic LiNH2BH3 and NaNH2BH3 constituents, with distinctly different coordination spheres of Li (3 N atoms and 1 hydride anion) and Na (6 hydride anions). Na[Li(NH2BH3)2], which may be viewed as a product of a Lewis acid (LiNH2BH3)/Lewis base (NaNH2BH3) reaction, is an important candidate for a novel lightweight hydrogen storage material. The title material decomposes at low temperature (with onset at 75°C, 6.0% mass loss up to 110°C, and an additional 3.0% up to 200°C) while evolving hydrogen contaminated with ammonia.