Synthesis, structure, and magnetic properties of the rare-earth zintl compounds Eu(14)MnPn(11) and Eu(14)InPn(11) (Pn = Sb, Bi)

New rare-earth transition-metal compounds Eu(14)MnPn(11) and Eu(14)InPn(11) (Pn = Sb, Bi) have been prepared in quantitative yield from heating stoichiometric amounts of the elements, which are sealed in a welded tantalum tube that is enclosed in a fused silica ampule, at 950-1200 degrees C. These compounds are isostructural with the Zintl compound Ca14AlSb11 and crystallize in the tetragonal space group I4(1)/acd (Z = 8). Single-crystal X-ray data (143 K) were refined for Eu14InSb11 (a = 17.280(5) Angstrom, c = 23.129(8) Angstrom, R-1 = 4.04%, wR2 = 8.65%) and Eu14MnBi11 (a = 17.632(4) Angstrom, c = 23.047(6) Angstrom, R-1 = 4.53%, wR2 = 7.83%). The structures of these compounds are compared with Eu14MnSb11 and other compounds of this structure type. Magnetization measurements show that Eu14MnSb11 and Eu14MnBi11 order at approximately 100 and 35 K, respectively. The effective moment in the paramagnetic state for Eu14MnSb11 is mu(eff) = 27.0(1) mu(B) and for Eu14MnBi11 is mu(eff) = 27.1(1) mu(B). Eu14InSb11 saturates with mu(sat) = 102 mu(B) at 5 K whereas Eu14MnBi11 does not saturate at 5 K with fields up to 5 T. Eu14InSb11 and Eu14InBi11 are both paramagnetic at high temperatures with mu(eff) = 30(1) mu(B) and 30.1(1) mu(B), respectively, and have transitions around 10 K to glassy and antiferromagnetic states, respectively.