Eu 4 Bi 3 : Crystal Structure, Magnetic and Electronic Properties

The EuBi system contains the phases Eu 5 Bi 3 , Eu 4 Bi 3 and Eu 11 Bi 10 . The structure types of these phases have been determined by powder X‐ray diffraction. Crystals of Eu 4 Bi 3 (cubic, space group I 4 3d; a = 9.920 Å, Z = 4, T = 130 K, R1/wR2 = 4.86/10.84%) were obtained in low yield by reaction of Eu, Mn, and Bi in the ratio 14:1:11 in a closed niobium tube (heating rate 30°C/h; reaction at 1050°C for 300 h, cooling rate 100°C/h). The crystal structure consists of distorted octahedra made up of six Bi coordinated to a central Eu atom. Eu is also coordinated to a three other Eu atoms and forms a three‐dimensional network composed of interconnected rings. The Bi atoms are coordinated to eight Eu atoms. High yields of Eu 4 Bi 3 can be prepared by reacting stoichiometric amount of the elements in a sealed tantalum tube at 1100°C for 24 h. Temperature dependent magnetic susceptibility is consistent with antiferromagnetic behavior with an ordering temperature of 18 K. The data could be fit with the Curie‐Weiss law and a moment of 7.38 μ B /Eu is obtained, consistent with all Eu atoms being Eu 11 . Temperature dependent resistivity indicates that Eu 4 Bi 3 is a metal with a room temperature resistance of 1.3 Ωcm.