Ternary rare earth silicides RE₂M₃Si₄ (RE = Sc, Y, Lu; M = Mo, W): Crystal structure, coloring and electronic properties

The ternary compounds Sc₂Mo₃Si₄, Y₂Mo₃Si₄, Lu₂Mo₃Si₄ and Sc₂W₃Si₄ have been synthesized using arc melting and structurally characterized using single crystal X-ray diffraction. The compounds are isostructural with Gd₅Si₄ but with coloring (order of the rare earth and transition metals) on the Gd site. In contrast to group 4 and 5 ternaries of the same type, we observe no site mixing between the rare earth and transition metals. The Y compound displays a different, less common coloring from the others and through DFT calculations and investigation of the solid solution between Sc₂Mo₃Si₄ and Y₂Mo₃Si₄ it is shown that the different coloring of the latter is only marginally more stable. The electronic structures of the ternary compounds have been investigated using DFT calculations, yielding densities of states very similar to Gd₅Si₄. These predict metallic behavior and no magnetism, which is confirmed through resistivity and magnetization measurements.