Ternary rare earth silicides RE sub(2)M sub(3)Si sub(4) (RE = Sc, Y, Lu; M = Mo, W): crystal structure, coloring and electronic properties

The ternary compounds Sc sub(2)Mo sub(3)Si sub(4), Y sub(2)Mo sub(3)Si sub(4), Lu sub(2)Mo sub(3)Si sub(4) and Sc sub(2)W sub(3)Si sub(4) have been synthesized using arc melting and structurally characterized using single crystal X-ray diffraction. The compounds are isostructural with Gd sub(5)Si sub(4) 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 Sc sub(2)Mo sub(3)Si sub(4) and Y sub(2)Mo sub(3)Si sub(4) 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 Gd sub(5)Si sub(4). These predict metallic behavior and no magnetism, which is confirmed through resistivity and magnetization measurements.