Remarkable Metal-Rich Ternary Chalcogenides Sc₁₄M₃Te₈ (M = Ru, Os)

In this novel motif, scandium atoms define infinite parallel chains of alternate trans-face-sharing cubes and pairs of square antiprisms in which each polyhedron is also centered by an M atom (M = Ru, Os). These chains are further linked into a three-dimensional structure by Sc(Te₂Te_4/2) octahedra. Physical property measurements show Sc₁₄Ru₃Te₈ to be metallic and Pauli-paramagnetic, consistent with the results of extended Hückel band structure calculations. Matrix effects are evident in the dimensions within the chains. The major interactions are Sc−M and Sc−Te.