Source of material Samples of the nominal composition Mg»Pdi_* with χ = 0.74, 0.75,0.76 and 0.78 were prepared by induction melting mixtures of the elements (Pd, 99.99 %; Mg, 99.99 %) in argon filled and weld-sealed tantalum ampoules. Subsequently, the ampoules were encapsulated in fused silica tubes and annealed at 773(5) Κ for three weeks. Finally, the ampoules were quenched in water. A single crystal of Mg3Pd with metallic lustre was obtained from the sample at the nominal composition

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... do.22-Chemical analyses on impurities of Ο, N, C, Η and Ta were performed using the carrier gas hot extraction, the combustion technique and ICP-MS spectroscopy, respectively. All impurities were below their respective limit of detection: Ο < 750 ppm, Ν < 150 ppm, C < 1000 ppm, Η < 32 ppm, Ta < 600 ppm. The microstructures of the samples were analyzed via microscopic examination in combination with EDXS to determine the number of phases and their composition. At 78.0 at-% and 76.0 at-% Mg the samples revealed two phases, Mg3Pd and the complex metallic alloy phase (CMA) Mg78.sPd2i.5 [ 1 ] . The sample at 75.0 at-% Mg is nearly single phase (CMA < 1%), whereas the sample at 74.0 at-% Mg consists of MgjPd and MgsPd2.