Synthesis, crystal structures and chemical bonding of RE5− xLi xGe4 (RE = Nd, Sm and Gd; x≃ 1) with the orthorhombic Gd5Si4 type.

The syntheses and single-crystal and electronic structures of three new ternary lithium rare earth germanides, RE5− xLi xGe4 (RE = Nd, Sm and Gd; x≃ 1), namely tetrasamarium lithium tetragermanide (Sm3.97Li1.03Ge4), tetraneodymium lithium tetragermanide (Nd3.97Li1.03Ge4) and tetragadolinium lithium tetragermanide (Gd3.96Li1.03Ge4), are reported. All three compounds crystallize in the orthorhombic space group Pnma and adopt the Gd5Si4 structure type (Pearson code oP36). There are six atoms in the asymmetric unit: Li1 in Wyckoff site 4 c, RE1 in 8 d, RE2 in 8 d, Ge1 in 8 d, Ge2 in 4 c and Ge3 in 4 c. One of the RE sites, i.e. RE2, is statistically occupied by RE and Li atoms, accounting for the small deviation from ideal RE4LiGe4 stoichiometry. [ABSTRACT FROM AUTHOR]