La2Sb, a layered superconductor with metal-metal bonds

We found that La(2)Sb with a layered structure composed of alternate stacking of La square nets and LaSb layers exhibits bulk superconductivity with a critical temperature of 5.3 K. This suggests that the presence of the square net with strong La-La metal bonding is essential for the emergence of superconductivity.

Geometric variations and electron localizations in intermetallics: PbFCl type compounds

The structural relations of the intermetallic compounds Cu2Sb, Mn2Sb, Fe2As, Mn2As, Cr2As, Sc2Sb as well as of YTiSi and ZrSiS, all adopting the PbFCl structure, are discussed. In the course of these investigations, the crystal structures of Mn2Sb, Mn2As and Fe2As have been redetermined and refined from single crystal data. Bandstructures have been calculated in the framework of Density Functional Theory. The bonding properties are compared on the basis of partial densities of states, of the Crystal Orbital Hamilton Population (COHP) and of the Electron Localization Function (ELF). The trend of thedelectrons to become more localized with increasing number leads to different bonding conditions in the compounds discussed.

Synthesis, Structure, and Bonding of Lu7Z2Te2 (Z = Ni, Pd, Ru). Linking Typical Tricapped Trigonal Prisms in Metal-Rich Compounds

The syntheses and structures of and bonding in the title compounds are described and compared with those for the isostructural orthorhombic Er(7)Ni(2)Te(2) (Imm2) and other related phases. Single-crystal data are reported for Z = Ni, Pd. The condensation of tricapped trigonal prisms (TTP) into sheets and the bridging of these by separate Lu atoms into a 3D structure are described. The interlayer separation, the Lu-Lu bonding achieved, and the polar Lu-Te bonding therewith are all affected by the size and valence energies of Te. The two Te spacers also exist in capped centered Lu(6)Te trigonal prisms. In terms of extended Hückel band analyses, the overall bonding for both Lu-Ni and Lu-Te are optimized energetically, but not for Lu-Lu. The average Lu-Lu overlap populations about each Lu appropriately increase with a decrease in the number of its Te neighbors.