ChemInform Abstract: Mg₃MnH₇, Containing the First Known Hexahydridomanganese(I) Complex.

Abstract

Mg 3 MnH 7 , Containing the First Known Hexahydridomanganese(I) Complex. -The new hydride compound of title is synthesized by reaction of MgH 2 with Mn powder in a 3:1 molar ratio (1070 K, 20 kbar, 120 min). The deuteride is prepared in the same way. The structure is investigated by neutron powder diffraction on the deuteride compound. The new phase crystallizes with the hexagonal Mg 3 ReH 7 type structure (space group P6 3 /mmc, Z = 2). Mg 3 MnH 7 decomposes between 530 K and 640 K under 1 bar hydrogen pressure into elemental manganese and magnesium. -(BORTZ, M.; BERTHEVILLE, B.; YVON, K.; MOVLAEV, E. A.; VERBETSKY, V. N.; FAUTH, F.; J. Alloys Compd. 279 (1998) 2, L8-L10; Lab. Cristallogr., Univ. Geneve, CH-1211 Geneve 4, Switz.; EN)

High Pressure Synthesis of Novel Mg(Ni<SUB>1&minus;<I>x</I></SUB>Cu<I><SUB>x</SUB></I>)<SUB>2</SUB> Hydrides (<I>x</I>=0&ndash;0.2)

“…Hydrogenation enthalpies of the hydrides at the dehydrogenation temperature were estimated from the endothermic peaks ( Table 2). The estimated values were 23-30 kJ/mol-H 2 , which are similar to those of well-known hydrogen storage alloys such as LaNi 5 and TiFe. It appeared that C36-type Mg(Ni 0:7 Cu 0:3 ) 2 has been hydrogenated under hydrogen pressure of 5 GPa; however, as mentioned previously, it was not hydrogenated at all.…”

High-pressure synthesis of novel hydrides Mg7−xAxTiH16−x (A=Li, Na, K; x=0–1.0) and their reversible hydrogen storage properties

“…In particular, ultrahigh pressure (UHP) with giga-pascal (GPa) by using the anvil-type apparatus would be very effective approach for developing novel Mg-based hydrides [10][11][12][13]. A series of fcc type hydrides Mg 7 MH 16 (M = Ti [14,15], V [16], Nb [17,18], Ta [19], Hf and Zr [20,21]) have been successfully synthesized under 8 GPa of hydrogen pressure.…”

Synthesis of FCC Mg–Ta hydrides using GPa hydrogen pressure method and their hydrogen-desorption properties

“…In order to solve this problem, it would be the best way to prepare new Mg-TM hydrides with good crystallinity. On the way of this approach, we have adopted a high-pressure synthesizing technique [5] and have succeeded to discover new Mg-based hydrides such as Mg 3 MnH 7 [6], Mg 3 MnH 6 [7], Mg 3 CrH 6 [8] and Mg 3 RE hydrides (RE: rare earth) [9] using hydrogen pressure up to 6 GPa. Furthermore, increasing the hydrogen pressure up to 8 GPa, we have also succeeded to synthesize Mg-rich hydride phases Mg 7 TMH x (TM = Ti, V and Nb) with Ca 7 Ge-type FCC super-lattice structure [10][11][12].…”