Ternary antimonide NaCd4Sb3: hydride synthesis, crystal structure and transport properties.

A new compound NaCd4Sb3 (R3‾m, a=4.7013(1) Å, c=35.325(1), Å, Z=3, T=100 K) featuring the RbCd4As3 structure type has been discovered in the Na−Cd−Sb system, in addition to the previously reported NaCdSb phase. NaCd4Sb3 and NaCdSb were herein synthesized using sodium hydride as the source of sodium. The hydride method allows for targeted sample composition, improved precursor mixing, and an overall quicker synthesis time when compared to traditional methods using Na metal as a precursor. The NaCd4Sb3 structure was determined from single‐crystal X‐ray diffraction and contained the splitting of a Cd site not seen in previous isostructural phases. NaCd4Sb3 decomposes into NaCdSb plus melt at 766 K, as determined via in‐situ high‐temperature PXRD. The electronic structure calculations predict the NaCd4Sb3 phase to be semi‐metallic, which compliments the measured thermoelectric property data, indicative of a p‐type semi‐metallic material. The crystal structure, elemental analysis, thermal properties, and electronic structure are herein discussed in further detail. [ABSTRACT FROM AUTHOR]