硼氢化铵
| 硼氢化铵 | |||
|---|---|---|---|
| |||
| 英文名 | Ammonium borohydride Ammonium tetrahydroborate | ||
| 别名 | 四氢合硼酸铵 | ||
| 识别 | |||
| CAS号 | 19193-35-2 
| ||
| 性质 | |||
| 化学式 | NH4BH4 | ||
| 外观 | 白色晶体[1] | ||
| 结构 | |||
| 晶体结构 | 面心立方（岩盐结构）[2] | ||
| 空间群 | Fm3m[2] | ||
| 相关物质 | |||
| 其他阴离子 | 氢化铵 | ||
| 其他阳离子 | 硼氢化钠 硼氢化钾 | ||
| 相关化学品 | 硼烷氨 氮化硼 | ||
| 若非注明，所有数据均出自标准状态（25 ℃，100 kPa）下。 | |||
硼氢化铵是一种无机化合物，化学式为NH4BH4，是一种在室温下不稳定的白色晶体，于1958年被发现。它是目前已知氢含量最高（ρm = 24.5 wt% H2）的固体化合物。[3]
制备
硼氢化钠和氟化铵在−60 °C（或−78 °C[3]）的液氨中反应，可以得到NH4BH4和NaF。[4]
- NaBH4 + NH4F → NH4BH4 + NaF
硼氢化钠和硫酸铵在四氢呋喃中的反应会有NH4BH4作为中间体产生，它会和之后生成的NH3BH3反应，进一步生成[(NH3)2BH2]BH4、B3N3H6等产物。[4]
- NH4BH4 + NH3BH3 → [(NH3)2BH2]BH4 + H2
性质及结构
硼氢化铵在−40 °C开始分解，25 °C经过6 h便只剩50%，分解反应的产物是[BNH6]x和氢气。[1]在固态时，它的分解产物是(NH3BH3)2；在含有痕量氨的乙醚中，它分解为NH3BH3。它在液氨中稳定。[5]
NH4BH4在1.5 GPa开始发生相变，由α相转变为β相，并在3.4~4.6 GPa转变为γ相。[6]
参考文献
- ^ 1.0 1.1 R. W. Parry, D. R. Schultz, P. R. Girardot. The Preparation and Properties of Hexamminecobalt(III) Borohydride, Hexamminechromium(III) Borohydride and Ammonium Borhydride 1. Journal of the American Chemical Society. 1958-1, 80 (1): 1–3 [2019-04-01]. ISSN 0002-7863. doi:10.1021/ja01534a001. （原始内容存档于2020-11-07） （英语）.
- ^ 2.0 2.1 Karkamkar, Abhijeet; Kathmann, Shawn M.; Schenter, Gregory K.; Heldebrant, David J.; Hess, Nancy; Gutowski, Maciej; Autrey, Tom. Thermodynamic and Structural Investigations of Ammonium Borohydride, a Solid with a Highest Content of Thermodynamically and Kinetically Accessible Hydrogen. Chemistry of Materials. 2009, 21 (19): 4356–4358. ISSN 0897-4756. doi:10.1021/cm902385c.
- ^ 3.0 3.1 Thomas K. Nielsen, Abhi Karkamkar, Mark Bowden, Flemming Besenbacher, Torben R. Jensen, Tom Autrey. Methods to stabilize and destabilize ammonium borohydride. Dalton Trans. 2013, 42 (3): 680–687 [2019-04-01]. ISSN 1477-9226. doi:10.1039/C2DT31591B （英语）.
- ^ 4.0 4.1 P. Veeraraghavan Ramachandran, Ameya S. Kulkarni. The role of ammonia in promoting ammonia borane synthesis. Dalton Transactions. 2016, 45 (41): 16433–16440 [2019-04-01]. ISSN 1477-9226. doi:10.1039/C6DT02925F （英语）.
- ^ David J. Heldebrant, Abhi Karkamkar, John C. Linehan, Tom Autrey. Synthesis of ammonia borane for hydrogen storage applications. Energy & Environmental Science. 2008, 1 (1): 156 [2019-04-01]. ISSN 1754-5692. doi:10.1039/b808865a （英语）.
- ^ Roxana Flacau, Yansun Yao, Dennis D. Klug, Serge Desgreniers, Christopher I. Ratcliffe. Structural phase transitions induced by pressure in ammonium borohydride. Physical Chemistry Chemical Physics. 2012, 14 (19): 7005 [2019-04-01]. ISSN 1463-9076. doi:10.1039/c2cp40160f （英语）.
拓展阅读
- Tom Autrey. Chemical approaches to on-board hydrogen storage. The road to reversibility in "Inorganic hydrides". Preprints - American Chemical Society, Division of Energy & Fuels, 2014. 59 (1): 4. CODEN: PACSCT.
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