title: AgCu3V4O12: a novel perovskite containing mixed-valence silver ions.
abstract: A novel silver-containing perovskite, AgCu3V4O12, was synthesized under high-pressure and high-temperature conditions. It crystallizes in an A-site-ordered perovskite structure (space group Im3), in which silver ions occupy the 12-coordinated A sites forming regular icosahedra, and exhibits metallic behavior. Bond-valence-sum calculations and X-ray photoemission spectroscopy reveal that Ag ions are present in the mixed-valence state, most likely attributable to the coexistence of Ag(+) and Ag(3+), unlike the case of well-known perovskite-type AgNbO3 and AgTaO3 containing only Ag(+) ions. We discuss metallic conduction in relation to electronic structure calculations.
authors: Department of Material Chemistry, Graduate School of Engineering, Kyoto University , Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors: Yasuhide
authors: Y
authors: Akizuki
authors: Ikuya
authors: I
authors: Yamada
authors: Koji
authors: K
authors: Fujita
authors: Hirofumi
authors: H
authors: Akamatsu
authors: Tetsuo
authors: T
authors: Irifune
authors: Katsuhisa
authors: K
authors: Tanaka