Synthesis and Characterization of New Multinary Selenides A10B18Se37 (A=Sn/Pb; B=In/Sb/Bi).

New multinary selenides with general formula A10B18Se37 (A=Sn/Pb; B=In/Sb or Sb/Bi) were synthesized with a new structure type in the monoclinic space group C2/m (No. 12), including Sn10In7Sb11Se37, Sn10Bi18Se37, Sn8.21Pb1.79Bi18Se37, and Sn3.84Pb6.16Sb5.68Bi12.32Se37. The crystal structure is related to Proudite‐Felbertalite homologous series and is made up of layered units ∞2M16Se23 derived from the octahedrally coordinated MSe6 with stepped layers of 16 octahedra overlapped by 8 octahedra units, and 1D ribbons ∞1M12Se14 with metal centers coordinated by 3 or 5 Se2− anions. Structural anisotropy leads to their layered shape and strong preferred orientation. The quinary selenide Sn3.84Pb6.16Sb5.68Bi12.32Se37 exhibits n‐type semiconducting behavior and thermoelectric properties with an optimized thermoelectric figure of merit (zT) reaching ∼0.09 at 440 K. Density functional theory (DFT) calculation on a charge‐balanced model with a triple supercell indicates its indirect band gap. [ABSTRACT FROM AUTHOR]