Structural phase transitions in Sr₂ScReO₆

Abstract

was heated under dynamic vacuum; at 130°C deuterium is released and LiMgAlD 6 is formed: LiMg(AlD 4 ) 3 → LiMgAlD 6 + 2Al + 3D 2 .At 180°C LiMgAlD 6 decomposes: LiMgAlD 6 → LiD + MgD 2 + Al + 3/2D 2 .The first reaction is endothermic; the second exothermic, indicating that LiMg(AlD 4 ) 3 is not thermodynamic stable.LiMg(AlD 4 ) 3 crystallizes in the monoclinic space group P2 1 /c with cell parameters: a = 8.37 Å, b = 8.74 Å, c = 14.30Å and β = 124.83°.The structure consists of isolated AlD 4 tetrahedra that are connected by octahedral Mg and Li atoms.LiMgAlD 6 crystallizes in the trigonal space group P321 with cell parameters: a = 7.98 Å and c = 4.38 Å.The structure consists of isolated AlD 6 octahedra tied together by hexa-coordinated Li and Mg atoms.A small amount of TiCl 3 was added to LiMg(AlD 4 ) 3 and mixed using the ball milling technique.The effect of addition of TiCl 3 was also studied for LiMgAlD 6 .