title: Synthesis, structure, and bonding of BaTl(3): an unusual competition between cluster and classical bonding in the thallium layers.
abstract: The new BaTl(3) compound has been synthesized and characterized by physical property measurements and electronic structure calculations. Its structure (Cmcm) is a new intermediate in the Ni(3)Sn family (P6(3)/mmc), and consists of thallium layers formed from two-center bond formation between the parallel chains of face-sharing octahedral clusters. The valence electron concentration (VEC) of the thallium layers is consistent with their two-dimensional nature, in comparison with those in other AX(3)-type compounds with one- or three-dimensional anionic networks with the same building blocks and different VECs. The unique geometric features of the anionic thallium layers bring on an unusual competition between inter- and intracluster bonds. Detailed studies of the energetics of BaTl(3) reveal for the first time the important role of cation-anion interactions in the bonding competition in such an anionic substructure.
authors.affiliation: Ames Laboratory-DOE and Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
authors.forename: Dong-Kyun
authors.initials: DK
authors.lastname: Seo
authors.forename: John D
authors.initials: JD
authors.lastname: Corbett