The ternary rare-earth chromium germanides RECrGe 3 (RE ) La-Nd, Sm) have been synthesized by direct reactions of the elements in the presence of Sn flux, or by arc-melting and annealing at 800 °C. Their structures were determined by single-crystal and powder X-ray diffraction. They adopt a hexagonal perovskite structure type (P6 3 /mmc, Z ) 2; a ) 6.2004(1)-6.0812(3) Å, c ) 5.7660(6)-5.6594(3) Å for RE ) La-Sm), unusual for an intermetallic compound, in which chains of face-sharing Cr-centered octahedra are linked by triangular Ge 3 clusters. Electrical resistivity measurements show metallic behavior for all RE members, with prominent transitions that coincide closely with ferromagnetic transitions (T c ranging from 60 to 155 K) seen in the magnetic susceptibility curves. Band structure calculations on LaCrGe 3 show the presence of a narrow, partially filled band with high DOS at the Fermi level.

Investigations in the ternary RE-Mn-Bi systems where RE is an early rare earth element have revealed the existence of the polybismuthides RE3MnBi5 (RE = La-Nd), previously known only for the Ce member, and the new compound Sm2Mn3Bi6. Their structures were determined from single-crystal X-ray diffraction data. The RE3MnBi5 compounds adopt the hexagonal inverse Hf5Cu3Sn-type structure (Pearson symbol hP18, space group P63/mcm, a = 9.7139(11)-9.5438(16) A, c = 6.4883(7)-6.4089(11) A for RE = La-Nd), containing chains of face-sharing Mn-centered octahedra. Sm2Mn3Bi6 adopts a new monoclinic structure type (Pearson symbol mP22, space group P21/m, a = 10.3917(8) A, b = 4.4557(3) A, c = 13.2793(10) A, beta = 108.0100(10) degrees ) in which the Mn centers are coordinated by Bi atoms in diverse geometries (distorted octahedral, trigonal bipyramidal, and distorted tetrahedral (seesaw)) and participate in extensive metal-metal bonding in the form of chains of Mn3 clusters. Homoatomic bonding interactions involving nominally anionic Bi atoms are manifested as one-dimensional Bi chains in RE3MnBi5 and as four-atom-wide Bi ribbons in Sm2Mn3Bi6. Electrical resistivity measurements on single crystals revealed metallic behavior with prominent transitions near 40 K for RE3MnBi5 and 50 K for Sm2Mn3Bi6. Magnetic susceptibility measurements showed that Pr3MnBi5 undergoes magnetic ordering near 25 K.

The cadmium analogue of the thermoelectric material “β-Zn4Sb3” has been prepared by reaction of a mixture of the elements with nominal stoichiometry “Cd57Sb43” at 430 °C. The composition of this phase, previously assumed to be “Cd4Sb3” in analogy to “β-Zn4Sb3”, has been determined to be approximately Cd12.7(1)Sb10, in agreement with recently revised formulations for the zinc analogue, which is now better described as Zn13Sb10. Single-crystal X-ray diffraction studies at 295 K showed that the structure of Cd12.7Sb10 (space group R3̄c, Z = 6, a = 13.0395(14) Å, c = 13.0346(14) Å) is similar to that of Zn13Sb10, but with a more complex set of interstitial metal sites. The structure remains unchanged at 193 K. The electrical resistivity of Cd12.7Sb10 decreases linearly with decreasing temperature and shows a modest upturn near 35 K.