Synthesis and characterization of the divalent samarium Zintl-phases SmMg2Bi2 and SmMg2Sb2.

Single crystals of LnMg 2 Bi 2 (Ln=Yb, Eu, Sm) and SmMg 2 Sb 2 were synthesized using Mg–Bi metal and Mg–Sb metal fluxes, respectively. The crystal structures are of the CaAl 2 Si 2 type with space group P 3 ̅ m1 (#164, Z =1): SmMg 2 Bi 2 ( a =4.7745(1) Å, c =7.8490(2) Å), EuMg 2 Bi 2 ( a =4.7702(1) Å, c =7.8457(2) Å), YbMg 2 Bi 2 ( a =4.7317(2) Å, c =7.6524(3) Å), and SmMg 2 Sb 2 ( a =4.6861(1) Å, c =7.7192(2) Å). Heat capacity, electrical transport, and magnetization of all bismuth containing phases were measured. The materials behave as “poor metals” with resistivity between 2 and 10 mΩ cm. Temperature independent Van Vleck paramagnetism is observed in SmMg 2 Bi 2 indicative of divalent samarium (Sm 2+ ) ions. [ABSTRACT FROM AUTHOR]