Synthesis, crystal and electronic structure of BaLi( x )Cd(13–x ) (x ≈ 2)

A new ternary phase has been synthesized and structurally characterized. BaLi( x )Cd(13–x ) (x ≈ 2) adopts the cubic NaZn(13) structure type (space group Fm [Formula: see text] c, Pearson symbol cF112) with unit cell parameter a = 13.5548 (10) Å. Structure refinements from single-crystal X-ray diffraction data demonstrate that the Li atoms are exclusively found at the centers of the Cd(12)-icosahedra. Since a cubic BaCd(13) phase does not exist, and the tetragonal BaCd(11) is the most Cd-rich phase in the Ba–Cd system, BaLi( x )Cd(13–x ) (x ≈ 2) has to be considered as a true ternary compound. As opposed to the typical electron count of ca. 27e-per formula unit for many known compounds with the NaZn(13) structure type, BaLi( x )Cd(13–x ) (x ≈ 2) only has ca. 26e-, suggesting that both electronic and geometric factors are at play. Finally, the bonding characteristics of the cubic BaLi( x )Cd(13–x ) (x ≈ 2) and tetragonal BaCd(11) are investigated using the TB-LMTO-ASA method, showing metallic-like behavior.