NaCdSb: This Zintl phase also belongs to the large family of ABX phases described above. NaCdSb crystallizes in an orthorhombic structure (P nma, no. 62) with distorted square pyramidal NaSb 5 units, which share edges with CdSb 4 tetrahedra. The structure can also be visualized as corrugated (CdSb) 1 layers arranged in a honeycomb structure and intercalated with Na (Figure ). The material is predicted to be semiconducting with a band gap of 0.41 eV. The individual TE quality factors ( p = 9.1, n = 13.6) yield an R = 1.50. Overall, we predict zT 300K of NaCdSb to be 75% of Mg 3 Bi 2 . Courteau et al. investigated the Na-Cd-Sb chemical system and the TE properties of NaCd 4 Sb 3 . 86 They found that NaCd 4 Sb 3 decomposes into NaCdSb at 766 K, whereas NaCdSb is stable up to 870 K. The measured zT at 300 K for NaCd 4 Sb 3 was 0.044, which was attributed to the high electrical resistivity of the material. However, the TE properties of NaCdSb have not been investigated yet and our predictions make a compelling case to further investigate the TE properties in the Na-Cd-Sb system.