ChemInform Abstract: Rare Earth Metal Rich Magnesium Compounds Ln₄NiMg (Ln: Y, Pr—Nd, Sm, Gd—Tm, Lu) — Synthesis, Structure, and Hydrogenation Behavior.

Abstract

Nickel I 7300Rare Earth Metal Rich Magnesium Compounds Ln4NiMg (Ln: Y, Pr-Nd, Sm, Gd-Tm, Lu) -Synthesis, Structure, and Hydrogenation Behavior. -The title compounds are prepared from the elements (sealed tantalum tubes, 1300 K, 2 min, 920 K, 2 h) and their structures are determined by powder and single crystal XRD. The Ln4NiMg compounds are isotypic with Gd4RhIn and crystallize in the cubic space group F43m with Z = 16. The structure consists of a three-dimensional network of edge-sharing NiLn 6 trigonal prisms. Mg 4 tetrahedra and additional Ln atoms are located within voids of this framework. The hydrogenation behavior of Y4NiMg and Gd4NiMg is studied. These compounds absorb up to 11 H atoms per formula unit under a hydrogen pressure of 1 MPa at room temperature. At temperatures >363 K decomposition to LnH2/LnH3 hydrides occurs. Gd4NiMg exhibits antiferromagnetic behavior below T N = 92 K, whereas its hydride Gd 4 NiMgH 11 is paramagnetic down to 1.8 K. -(TUNCEL, S.; ROQUEFERE, J. G.; STAN, C.; BOBET, J.-L.; CHEVALIER, B.; GAUDIN, E.; HOFFMANN, R.-D.; RODEWALD, U. C.; POETTGEN*, R.; J. Solid

The isothermal section of the phase diagram of Sm–Cu–Mg ternary system at 670 K

“…Although, among the RE-T-Mg and related ternary systems a few series of ternary phases are known, only for the Y-Cu-Mg [14], La-Ag-Mg [15] and La-Co-Mg [16] systems, phase diagrams were reported. These known ternary phases are: RETMg with the MoAlB [17] or ZrNiAl [18] structural types, RET 4 Mg (MgCu 4 Sn type) [19], RET 2 Mg and RETMg 2 (MnCu 2 Al type) [20,21], RECuMg 4 (UCoAl 4 type) [22], RE 23 T 7 Mg 4 (Pr 23 Ir 7 Mg 4 type) and R 4 TMg (Gd 4 RhIn type) [23][24][25]. In this work, the experimental results of the investigations of isothermal section of the Sm-Cu-Mg ternary system phase diagram at 670 K, are reported and discussed together with crystal structures of new ternary compounds obtained.…”