The crystal structure and stability of K2NaAlH6

被引：37
作者：
Sorby, M. H.
Brinks, H. W.
Fossdal, A.
Thorshaug, K.
Hauback, B. C.
机构：
[1] Inst Energy Technol, Dept Phys, N-2027 Kjeller, Norway
[2] SINTEF Mat & Chem, N-0314 Oslo, Norway
来源：
JOURNAL OF ALLOYS AND COMPOUNDS | 2006年 / 415卷 / 1-2期
关键词：
hydrogen storage materials; alanates; ball-milling; crystal structure; pressure-composition isotherms;
D O I：
10.1016/j.jallcom.2005.08.010
中图分类号：
O64 [物理化学（理论化学）、化学物理学];
学科分类号：
070304 ; 081704 ;
摘要：
The mixed alanate K2NaAlH6 has been synthesised by ball-milling a mixture of KH and NaAlH4 and subsequent annealing at 150 degrees C under a stabilizing hydrogen pressure. It takes a cubic ordered perovskite-type structure (space group Fm (3) over barm, a = 8.118(l) A) where the ideal octahedral AlH63- units form a cubic close-packed structure with K+ in all tetrahedral sites and Na+ in all octahedral sites. K2NaAlH6 with 1 mol% TiF3 decompose quickly and reversibly with a flat plateau. Pressure-composition isotherms have been measured at five temperatures in the range 280-325 degrees C. The decomposition enthalpy and entropy were determined to 98(2) kJ/mol H-2 and 150(4) J/(K mol H-2) from the van't Hoff equation. (c) 2005 Elsevier B.V. All rights reserved.
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页码：284 / 287
页数：4
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