H. Chu, Guotao Wu, Zhitao Xiong
Oct 18, 2010
Citations
1
Influential Citations
89
Citations
Quality indicators
Journal
Chemistry of Materials
Abstract
A new type of hydrogen storage material—namely, calcium borohydride diammoniate (Ca(BH4)2·2NH3), is synthesized by reacting calcium borohydride and 2 equiv of ammonia. Structural analyses show that this complex has an orthorhombic structure (space group Pbcn) with unit-cell parameters of a = 6.4160 A, b = 8.3900 A, c = 12.7020 A, and V = 683.75 A3, in which Ca2+ coordinates with four −BH4 groups two −NH3 groups. The presence of NH3 in the crystal lattice facilitates the formation of B−H···H−N dihydrogen bonding. As a consequence, the bond lengths of B−H and N−H are increased with comparison to Ca(BH4)2 and NH3, respectively. Our experimental results show that more than 11.3 wt % hydrogen can be released exothermically from Ca(BH4)2·2NH3 in a closed vessel at a temperature as low as 250 °C.