Premium
Structure and Thermoelectric Properties of the New Quaternary Bismuth Selenides A 1− x M 4− x Bi 11+ x Se 21 (A=K and Rb and Cs; M=Sn and Pb)—Members of the Grand Homologous Series K m (M 6 Se 8 ) m (M 5+ n Se 9+ n )
Author(s) -
Mrotzek Antje,
Chung DuckYoung,
Ghelani Nishant,
Hogan Tim,
Kanatzidis Mercouri G.
Publication year - 2001
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20010504)7:9<1915::aid-chem1915>3.0.co;2-2
Subject(s) - monoclinic crystal system , bismuth , crystallography , chalcogenide , octahedron , alkali metal , crystal structure , materials science , chalcogen , thermoelectric effect , chemistry , physics , metallurgy , thermodynamics , organic chemistry
Several members of the new family A 1− x M 4− x Bi 11+ x Se 21 (A=K, Rb, Cs; M=Sn, Pb) were prepared by direct combination of A 2 Se, Bi 2 Se 3 , Sn (or Pb), and Se at 800 °C. The single‐crystal structures of K 0.54 Sn 3.54 Bi 11.46 Se 21 , K 1.46 Pb 3.08 Bi 11.46 Se 21 , Rb 0.69 Pb 3.69 Bi 11.31 Se 21 , and Cs 0.65 Pb 3.65 Bi 11.35 Se 21 were determined. The compounds A 1− x M 4− x Bi 11+ x Se 21 crystallize in a new structure type with the monoclinic space group C 2/m, in which building units of the Bi 2 Te 3 and NaCl structure type join to give rise to a novel kind of three‐dimensional anionic framework with alkali‐ion‐filled tunnels. The building units are assembled from distorted, edge‐sharing (Bi,Sn)Se 6 octahedra. Bi and Sn/Pb atoms are disordered over the metal sites of the chalcogenide network, while the alkali site is not fully occupied. A grand homologous series K m (M 6 Se 8 ) m (M 5+ n Se 9+ n ) has been identified of which the compounds A 1− x M 4− x Bi 11+ x Se 21 are members. We discuss here the crystal structure, charge‐transport properties, and very low thermal conductivity of A 1− x M 4− x Bi 11+ x Se 21 .