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A 10 LaCdSb 9 (A=Ca, Yb): A Highly Complex Zintl System and the Thermoelectric Properties
Author(s) -
Wang Jian,
Xia ShengQing,
Tao XuTang
Publication year - 2013
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201200827
Subject(s) - thermoelectric effect , zintl phase , orthorhombic crystal system , thermal stability , crystallography , thermoelectric materials , materials science , thermal conductivity , differential scanning calorimetry , electrical resistivity and conductivity , ion , seebeck coefficient , crystal structure , chemistry , analytical chemistry (journal) , physics , thermodynamics , chromatography , organic chemistry , composite material , quantum mechanics
Two new Zintl compounds A 10 LaCdSb 9 (A=Ca, Yb), namely, Ca 9.81(1) La 0.97(1) Cd 1.23(1) Sb 9 and Yb 9.78(1) La 0.97(1) Cd 1.24(1) Sb 9 , have been designed and synthesized by applying the Zintl concept. Although both compounds are isoelectronic with their Ca 11 InSb 9 and Yb 11 InSb 9 analogues, they crystallize in a new structure type with the orthorhombic space group Ibam (No.72) and feature very complex anion structures, which are composed of unique [Cd 2 Sb 6 ] 12− clusters, dumbbell‐shaped [Sb 2 ] 4− dimers, and isolated [Sb] 3− anions. For Yb 9.78(1) La 0.97(1) Cd 1.24(1) Sb 9 , an extremely low lattice thermal conductivity of 0.29 W m −1 K −1 was observed at 875 K, which almost approaches the lowest reported limit of nonglassy or nonionically conducting bulk materials . According to thermogravimetric (TG) and differential scanning calorimetry (DSC) analyses, both compounds show very good thermal stability and no melting or phase transition processes were found below 1173 K. Although related thermoelectric property studies on Yb 9.78(1) La 0.97(1) Cd 1.24(1) Sb 9 only present a maximum ZT of 0.11 at 920 K, owing to its low Seebeck coefficients, these materials are still very promising for their high temperature stability and low thermal conductivity . Furthermore, as mixed cations exist with different charges, it makes this system very flexible in tuning the related electrical properties.