Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1613371 | Journal of Alloys and Compounds | 2013 | 5 Pages |
Abstract
Dehydrogenation properties and crystal structure of the double anion complex hydride Mg(BH4)(NH2) were studied by thermal analyses and synchrotron X-ray diffraction. The stoichiometric mixture of Mg(BH4)2 and Mg(NH2)2 were ball-milled and then heated to 453 K to form Mg(BH4)(NH2) crystal. The dehydrogenation of Mg(BH4)(NH2) occurs in two-stage at 513 K and 688 K. The following reaction sequence is suggested by the results of thermal analyses; Mg(BH4)(NH2) â MgH2 + BN + 2H2 (7.3 mass% weight loss) â Mg + BN + 3H2 (11.0 mass% weight loss in total). The dehydrogenation temperature of Mg(BH4)(NH2) is approximately 50 K lower than that of the other double anion complex Li2(BH4)(NH2). The crystal structure of Mg(BH4)(NH2) was determined by the measurement at 300 K (crystal system: tetragonal, space group: I41 (No. 80), lattice constants: a = 5.792(1), c = 20.632(4) Ã
at 300Â K). In the crystal of Mg(BH4)(NH2), the cation (Mg2+) and the anions (BH4- and NH2-) are stacked alternately along the c-axis direction. The Mg2+ cation is tetrahedrally coordinated with two BH4- anions and two NH2- anions.
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
Tatsuo Noritake, Kazutoshi Miwa, Masakazu Aoki, Mitsuru Matsumoto, Shin-ichi Towata, Hai-Wen Li, Shin-ichi Orimo,