Synthesis and Crystal Structure of the Zintl Phases NaSrSb, NaBaSb and NaEuSb
This work details the synthesis and the crystal structures of the ternary compounds NaSrSb, NaBaSb and NaEuSb. They are isostructural and adopt the hexagonal ZrNiAl-type structure (space group P6¯2m; Pearson code hP9). The structure determination in all three cases was performed using single-crystal X-ray diffraction methods. The structure features isolated Sb3– anions arranged in layers stacked along the crystallographic c-axis. In the interstices, alkali and alkaline-earth metal cations are found in tetrahedral and square pyramidal coordination environments, respectively. The formal partitioning of the valence electrons adheres to the valence rules, i.e., Na+Sr2+Sb3–, Na+Ba2+Sb3– and Na+Eu2+Sb3– can be considered as Zintl phases with intrinsic semiconductor behavior. Electronic band structure calculations conducted for NaBaSb are consistent with this notion and show a direct gap of approx. 0.9 eV. Additionally, the calculations hint at possible inverted Dirac cones, a feature that is reminiscent of topological quantum materials.
This article was originally published in Materials. The version of record is available at: https://doi.org/10.3390/ma16041428
antimonides , crystal structure , thermoelectrics , topological insulator , Zintl phases
Wang, Yi, and Svilen Bobev. 2023. "Synthesis and Crystal Structure of the Zintl Phases NaSrSb, NaBaSb and NaEuSb" Materials 16, no. 4: 1428. https://doi.org/10.3390/ma16041428