title: AuCuSe(4): a mixed polychalcogenide with Se(3)(2-) and Se(2-) anions.
abstract: The polychalcogenide compound AuCuSe(4) crystallizes in the monoclinic space group P2(1)/m with a = 4.318(2) A, b = 7.447(1) A, c = 8.099(1) A, beta = 93.33(2)(o), and Z = 2. The structure of AuCuSe(4) is a unique three-dimensional framework assembled from formally Au(3+) and Cu(+) ions and Se(3)(2-) and Se(2-) fragments. Conceptually, the framework is composed of one-dimensional [Au(Se(3))Se](n)(n-) chains linked by Cu(+) atoms. The Au atoms adopt a square planar geometry while Cu atoms adopt a severely distorted tetrahedral geometry. The Se(3)(2-) ligand in this structure shows an unprecedented ligation mode using both its terminal and internal selenium atoms. The material is a p-type narrow gap semiconductor with a band gap of approximately 0.52 eV.
authors.affiliation: Department of Chemistry and Center for Fundamental Materials Research, Michigan State University, East Lansing, Michigan 48824-1322, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Park
authors.forename: M G
authors.initials: MG
authors.lastname: Kanatzidis