TY - JOUR
T1 - High-pressure synthesis of novel hydrides in Mg-RE-H systems (RE = Y, La, Ce, Pr, Sm, Gd, Tb, Dy)
AU - Kamegawa, Atsunori
AU - Goto, Y.
AU - Kakuta, H.
AU - Takamura, H.
AU - Okada, M.
N1 - Funding Information:
This work has been supported in part by NEDO program and 21st century COE (Center of Excellence) program.
PY - 2006/2/9
Y1 - 2006/2/9
N2 - The high-pressure synthesis of new hydrides of Mg-RE-H systems, where RE = Y, La, Ce, Pr, Sm, Gd, Tb and Dy, were conducted by using a cubic-anvil-type apparatus, and their crystal structure, thermal stabilities and hydrogen contents were investigated. In Mg-Y-H system, newly found MgY2H y with a FCC-type structure has been prepared. In MgH2-x mol% REH (REH = LaH3, CeH2.5 and PrH3), new hydrides with primitive tetragonal structure were synthesized around x = 25-33 under GPa-order high pressures. The lattice constants were a = 0.8193 nm, c = 0.5028 nm, a = 0.8118 nm, c = 0.4979 nm and a = 0.8058 nm, c = 0.4970 nm at x = 25 in Mg-La, Ce and Pr systems, respectively. The hydrogen contents of the novel compounds were 4.1, 3.7 and 3.9 mass% in Mg-La, Ce and Pr systems, respectively, and the chemical formulae were found to correspond to Mg 3LaH9, Mg3CeH8.1 and Mg 3PrH9. The new hydrides decomposed into Mg and rare-earth hydride at about 600 K (Mg3LaH9: 614 K, Mg 3CeH8.1: 609 K, Mg3PrH9: 630 K) with an endothermic reaction. In MgH2-x mol% hREH (hREH = GdH 3, TbH3 and DyH3), new hydrides with FCC-type structure were synthesized around x = 67.
AB - The high-pressure synthesis of new hydrides of Mg-RE-H systems, where RE = Y, La, Ce, Pr, Sm, Gd, Tb and Dy, were conducted by using a cubic-anvil-type apparatus, and their crystal structure, thermal stabilities and hydrogen contents were investigated. In Mg-Y-H system, newly found MgY2H y with a FCC-type structure has been prepared. In MgH2-x mol% REH (REH = LaH3, CeH2.5 and PrH3), new hydrides with primitive tetragonal structure were synthesized around x = 25-33 under GPa-order high pressures. The lattice constants were a = 0.8193 nm, c = 0.5028 nm, a = 0.8118 nm, c = 0.4979 nm and a = 0.8058 nm, c = 0.4970 nm at x = 25 in Mg-La, Ce and Pr systems, respectively. The hydrogen contents of the novel compounds were 4.1, 3.7 and 3.9 mass% in Mg-La, Ce and Pr systems, respectively, and the chemical formulae were found to correspond to Mg 3LaH9, Mg3CeH8.1 and Mg 3PrH9. The new hydrides decomposed into Mg and rare-earth hydride at about 600 K (Mg3LaH9: 614 K, Mg 3CeH8.1: 609 K, Mg3PrH9: 630 K) with an endothermic reaction. In MgH2-x mol% hREH (hREH = GdH 3, TbH3 and DyH3), new hydrides with FCC-type structure were synthesized around x = 67.
KW - High pressure
KW - Hydride
KW - Magnesium
KW - Rare earth
KW - Thermal stability
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U2 - 10.1016/j.jallcom.2005.04.093
DO - 10.1016/j.jallcom.2005.04.093
M3 - Conference article
AN - SCOPUS:31344449563
VL - 408-412
SP - 284
EP - 287
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
SN - 0925-8388
T2 - Proceedings of the Rare Earths'04 in Nara, Japan
Y2 - 7 November 2004 through 12 November 2004
ER -