title: Localized versus delocalized bonding in the K5Bi4 metallic salt.
abstract: The electronic structure of one member of the A(5)Pn(4) family of metallic salts, K(5)Bi(4), has been studied by means of first-principles density functional calculations. It is shown that the alkali and pnictide orbitals mix considerably providing for a large covalent bonding contribution to the stability of the compound. It is suggested that solids of the A(5)Pn(4) family of compounds (A = K, Rb, Cs; Pn = As, Sb, Bi) should have better conductivity in the direction perpendicular to the plane of the tetrameric pnictide units and that the low-temperature transition in the antimonides is an order-disorder transition associated with one of the alkali positions.
authors.affiliation: Departament de Química Inorgànica and Centre de Recerca en Química Teòrica (CeRQT), Universitat de Barcelona, Diagonal 647, 08028 Barcelona, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Rodríguez-Fortea
authors.forename: Enric
authors.initials: E
authors.lastname: Canadell