Solid-solution Zintl compounds with the formula Eu11Cd6-xZnxSb12 have been synthesized from the elements as single crystals using a tin flux according to the stoichiometry Eu:Cd:Zn:Sb:Sn of 11:6-xp:xp:12:30 with xp = 0, 1, 2, 3, 4, 5, and 6, where xp is the preparative amount of Zn employed in the reaction. The crystal structures and the compositions were established by single-crystal as well as powder X-ray diffraction and wavelength-dispersive X-ray analysis measurements. The title solid-solution Zintl compounds crystallize isostructurally in the centrosymmetric monoclinic space group C 2/m (No. 12, Z = 2) as the Sr11Cd6Sb12 structure type (Pearson symbol mC58). There is a miscibility gap at 3 xp 4 where the major product crystallizes in a disordered structure related to the Ca9Mn4Bi9 structure type; otherwise, for all other compositions, the Sr11Cd6Sb12 structure is the majority phase. Eu11Cd6Sb12 shows lower lattice thermal conductivity relative to Eu11Zn6Sb12 consistent with its higher mean atomic weight, and as anticipated, the solid-solution samples of Eu11Cd6-xZnxSb12 have effectively reduced lattice thermal conductivities relative to the end member compounds. Eu11.0(1)Cd4.5(2)Zn1.5(2)Sb12.0(1) exhibits the highest zT value of >0.5 at around 800 K which is twice as large as the end member compounds.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Materials Chemistry