Synthesis and crystal structures of RE₇Zn_21+xSi_2–x [RE = Ce, Pr, and Nd; 0.09 (1) < x < 0.95 (1)]

The structures of the ternary compounds RE₇Zn_21+xSi_2−x [RE = Ce, Pr, and Nd; 0.09 (1) < x < 0.95 (1)] are reported. Important structural features in these compounds are the large polyhedral cages made up of Zn atoms and the Si atoms in trigonal planar coordination. A small occupational Zn–Si disorder is found at the Si site.

The series RE₅Li₂Sn₇ (RE = Ce, Pr, Nd, Sm) revisited: crystal structure of RE₅Li_2−xSn_7+x [0 ≤ x ≤ 0.03 (1)]

Polar inter­metallic phases with complex structures are reported in the RE–Li–Sn system (RE = Ce, Pr, Nd, Sm). They crystallize in the chiral ortho­rhom­bic space group P2₁2₁2₁ (No. 19), which is relatively uncommon among inter­metallic phases.