Synthesis, crystal and electronic structure of BaLixCd13-x (x ≈ 2)

A new ternary phase has been synthesized and structurally characterized. BaLixCd13-x (x approximate to 2) adopts the cubic NaZn13 structure type (space group Fm (3) over barc, Pearson symbol cF112) with unit cell parameter a = 13.5548 (10) angstrom. Structure refinements from single-crystal X-ray diffraction data demonstrate that the Li atoms are exclusively found at the centers of the Cd u -icosahedra. Since a cubic BaCd13 phase does not exist, and the tetragonal BaCd11 is the most Cd-rich phase in the Ba-Cd system, BaLixCd13-x (x approximate to 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 NaZn13 structure type, BaLi(x)Cdo(13-x) (x approximate to 2) only has ca. 26e-, suggesting that both electronic and geometric factors are at play. Finally, the bonding characteristics of the cubic BaLixCd13-x (x approximate to 2) and tetragonal BaCd11 are investigated using the TB-LMTO-ASA method, showing metallic-like behavior.

Automated summary

A new ternary phase BaLixCd13-x with cubic NaZn13 structure type has been synthesized and characterized. Li atoms are found exclusively at the centers of the Cd u -icosahedra. BaLixCd13-x has a lower electron count compared to other compounds with NaZn13 structure type. The bonding characteristics of BaLixCd13-x and BaCd11 were investigated and both show metallic-like behavior.