title: A U(V) chalcogenide: synthesis, structure, and characterization of K2Cu3US5.
abstract: The compound K2Cu3US5 was obtained by the reaction of K2S, UCl4, CuCl, and S at 973 K. K2Cu3US5 crystallizes in a new structure type in space group Cmcm of the orthorhombic system in a cell of dimensions a = 3.9374(6) A, b = 13.813(2) A, c = 17.500(3) A, and V = 951.8(2) A3 at 153 K. The structure comprises (2)(infinity)[UCu3S52-] slabs separated by K+ cations. The slabs are built from CuS4 tetrahedra and US6 octahedra. Their connectivity differs from other known octahedral/tetrahedral packing patterns. In the temperature range 130-300 K the compound exhibits Curie-Weiss magnetic behavior with mu(eff) = 2.45(8) mu(B). This result together with both the bond distances and bond valence calculations and the absence of a Cu2+ ESR signal support the formulation of the above compound as K+2Cu+3U5+S2-5.
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, IL 60208, USA.
authors.forename: Danielle L
authors.initials: DL
authors.lastname: Gray
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Backus
authors.forename: Hans-Albrecht Krug
authors.initials: HA
authors.lastname: von Nidda
authors.forename: S
authors.initials: S
authors.lastname: Skanthakumar
authors.forename: Alois
authors.initials: A
authors.lastname: Loidl
authors.forename: L
authors.initials: L
authors.lastname: Soderholm
authors.forename: James A
authors.initials: JA
authors.lastname: Ibers