TY - JOUR
T1 - Syntheses, crystal structures, and thermal analyses of solvent-free Ca(AlD4)2 and CaAlD5
AU - Sato, T.
AU - Sørby, M. H.
AU - Ikeda, K.
AU - Sato, S.
AU - Hauback, B. C.
AU - Orimo, S.
N1 - Funding Information:
A part of this work was financially supported by a Grant-Aid for Science Research ( 20760462 ) from the Ministry of Education, Culture, Sports, Science and Technology of Japan, by the Japan Society for the Promotion of Science; by the Global COE Program “Materials Integration, Tohoku University,” MEXT, Japan; and by Exploratory Research Program for Young Researchers at Tohoku University. The authors would like to thank Ms. H. Ohmiya for technical supports. The skillful assistance by the project team at the Swiss-Norwegian Beam Line, ESRF is gratefully acknowledged.
PY - 2009/11/13
Y1 - 2009/11/13
N2 - Solvent-free Ca(AlD4)2 and CaAlD5 were synthesized directly by mechanochemical milling of CaD2 and AlD3 in the molar ratios of 1:2 and 1:1, respectively, under deuterium gas pressure of 0.3 MPa. The products were characterized by high-resolution synchrotron radiation powder X-ray diffraction (SR-PXD), powder neutron diffraction (PND), Raman spectroscopy, and thermogravimetry (TG) analysis. The crystal structure of Ca(AlD4)2 was determined and refined with the SR-PXD and PND data. It takes an orthorhombic Ca(BF4)2-type structure with a = 13.4491(27) Å, b = 9.5334(19) Å, and c = 9.0203(20) Å in the space group Pbca (No. 61) and Z = 8. The Raman spectrum shows bending and stretching modes of the AlD4 tetrahedron at 480-650 cm-1 and 1290-1340 cm-1, respectively. TG analysis showed that Ca(AlD4)2 releases 4.8 wt.% of deuterium gas at the onset-temperature of 427 K. The crystal structure of CaAlD5 was determined and refined from the PND data and was found to be a monoclinic α-SrAlF5-type structure with a = 9.8000(19) Å, b = 6.9081(13) Å, c = 12.4503(23) Å, and β = 137.936(4)° in the space group P21/c (No. 14) and Z = 8. The Raman spectrum of CaAlD5 shows bending and stretching modes of the AlD6 octahedron at 725 and 1060-1170 cm-1, respectively. From TG analysis, CaAlD5 releases 7.1 wt.% of deuterium gas at the onset-temperature of 554 K.
AB - Solvent-free Ca(AlD4)2 and CaAlD5 were synthesized directly by mechanochemical milling of CaD2 and AlD3 in the molar ratios of 1:2 and 1:1, respectively, under deuterium gas pressure of 0.3 MPa. The products were characterized by high-resolution synchrotron radiation powder X-ray diffraction (SR-PXD), powder neutron diffraction (PND), Raman spectroscopy, and thermogravimetry (TG) analysis. The crystal structure of Ca(AlD4)2 was determined and refined with the SR-PXD and PND data. It takes an orthorhombic Ca(BF4)2-type structure with a = 13.4491(27) Å, b = 9.5334(19) Å, and c = 9.0203(20) Å in the space group Pbca (No. 61) and Z = 8. The Raman spectrum shows bending and stretching modes of the AlD4 tetrahedron at 480-650 cm-1 and 1290-1340 cm-1, respectively. TG analysis showed that Ca(AlD4)2 releases 4.8 wt.% of deuterium gas at the onset-temperature of 427 K. The crystal structure of CaAlD5 was determined and refined from the PND data and was found to be a monoclinic α-SrAlF5-type structure with a = 9.8000(19) Å, b = 6.9081(13) Å, c = 12.4503(23) Å, and β = 137.936(4)° in the space group P21/c (No. 14) and Z = 8. The Raman spectrum of CaAlD5 shows bending and stretching modes of the AlD6 octahedron at 725 and 1060-1170 cm-1, respectively. From TG analysis, CaAlD5 releases 7.1 wt.% of deuterium gas at the onset-temperature of 554 K.
KW - Alanates
KW - Hydrogen storage
KW - Neutron diffraction
KW - Raman spectroscopy
KW - Thermogravimetry
KW - X-ray diffraction
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U2 - 10.1016/j.jallcom.2009.07.164
DO - 10.1016/j.jallcom.2009.07.164
M3 - Article
AN - SCOPUS:70350619472
SN - 0925-8388
VL - 487
SP - 472
EP - 478
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
IS - 1-2
ER -