Structure and Hydrogen Storage Properties of Calcium Borohydride Diammoniate
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- 作者：Hailiang Chu ; Guotao Wu ; Zhitao Xiong ; Jianping Guo ; Teng He ; Ping Chen
- 刊名：Chemistry of Materials
- 出版年：2010
- 出版时间：November 9, 2010
- 年：2010
- 卷：22
- 期：21
- 页码：6021-6028
- 全文大小：848K
- 年卷期：v.22,no.21(November 9, 2010)
- ISSN：1520-5002
文摘
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 Å, b = 8.3900 Å, c = 12.7020 Å, and V = 683.75 Å3, 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.