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

• Synthesized and characterized single crystals of two new Zintl compounds SmMg2Sb2 and SmMg2Bi2.
• Stabilization of divalent samarium in mixed magnesium rich fluxes.
• Magnetic data has been analyzed which reveals the divalency of Sm in SmMg2Bi2.

Single crystals of LnMg2Bi2 (Ln=Yb, Eu, Sm) and SmMg2Sb2 were synthesized using Mg–Bi metal and Mg–Sb metal fluxes, respectively. The crystal structures are of the CaAl2Si2 type with space group P  3̅m1 (#164, Z=1): SmMg2Bi2 (a=4.7745(1) Å, c=7.8490(2) Å), EuMg2Bi2 (a=4.7702(1) Å, c=7.8457(2) Å), YbMg2Bi2 (a=4.7317(2) Å, c=7.6524(3) Å), and SmMg2Sb2 (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 SmMg2Bi2 indicative of divalent samarium (Sm2+) ions.

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