La₆Pd₁₃Cd₄ and Ce₆Pd₁₃Cd₄ with palladium-centred rare earth octahedra: synthesis, structure, and chemical bonding

he palladium-rich cadmium compounds La6Pd13Cd4 and Ce6Pd13Cd4 were synthesized by induction melting the elements in sealed tantalum ampoules and subsequent annealing. They were characterized by X-ray powder and single-crystal diffraction: Na16Ba6N type, ...

Linear infinite cadmium chains in CaAu4Cd2 and other intermetallics with YbMo2Al4-type structure

International audienceNew YbMo2Al4-type cadmium compounds CaAu4Cd2, SrAu4Cd2, and EuAu4Cd2 were synthesized from the elements in sealed tantalum tubes. The structures of CaAu4Cd2 (I4/mmm, a = 710.7(1), c = 550.2(3) pm, wR2 = 0.026, 168 F 2 values, 10 variables) and EuAu4.80Cd1.20 (a = 716.6(1), c = 545.9(1) pm, wR2 = 0.024, 167 F 2 values, 11 variables) were refined from X-ray single-crystal diffractometry data. The gold and cadmium atoms show different substructures: Au4 squares (279 pm Au-Au in CaAu4Cd2) and cadmium chains (275 pm Cd-Cd in CaAu4Cd2). EuAu4Cd2 forms a solid solution EuAu4+x Cd2−x up to x ≈ 1, where almost every other cadmium atom within the chains is substituted by gold. Chemical bonding analyses on CaAu4Cd2 shows almost complete charge transfer from calcium to the [Au4Cd2] network. Bader charge analysis classifies CaAu4Cd2 as an auride. EuAu4Cd2 shows Curie-Weiss behavior above 25 K with an experimental magnetic moment of 7.86 μB/Eu atom, near to the free ion value of 7.94 μB for Eu2+ and orders ferromagnetically at T C = 16.3(5) K. 151Eu Mössbauer spectra show a single signal at an isomer shift of about −10 mm/s, compatible with divalent europium. At 5 K, and therefore clearly below T C, magnetic hyperfine splitting is observed

New ternary intermetallics based on magnesium for hydrogen storage : the fishing approach

Magnesium allows obtaining a good hydrogen storage capacity in terms of weight percentage but its use is limited by high stability of the hydride and slow kinetics. The kinetics can be improved by (i) mechanical grinding, cold rolling (or other severe plastic deformation) and (ii) addition of various elements (catalysts or activators)