title: La9Sb16Br3 and Ce9Sb16Cl3: stars and stripes in rare earth halide and intermetallic compounds.
abstract: The title compounds were synthesized from Ln, LnX(3) (Ln = La, Ce; X = Cl, Br), and Sb under an Ar atmosphere at 950 degrees C. They crystallize in the space group P6(3)/m (No. 176) with lattice constants a = 21.232(5) and 20.862(2) Angstroms and c = 4.323(2) and 4.2728(7) Angstroms for La(9)Sb(16)Br(3) and Ce(9)Sb(16)Cl(3), respectively. The solids are the most metal-rich members in the reduced rare earth metal halide family and contain partial structures which are characteristic of reduced halides and intermetallic phases. These are the [Ln(6)X(6)](infinity) hexagon stars, Sb-centered [Ln(3)Sb](infinity) trigonal prismatic columns, and stripes of Sb square meshes. Computational analysis indicates that their electronic structure is valence-precise in the reduced halide part, but electron-deficient in the intermetallic part. Susceptibility and resistivity measurements reveal the metallic nature of the compounds.
authors.affiliation: Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, 60115, USA. zheng@cz.chem.niu.edu
authors.forename: Chong
authors.initials: C
authors.lastname: Zheng
authors.forename: Hansjürgen
authors.initials: H
authors.lastname: Mattausch
authors.forename: Arndt
authors.initials: A
authors.lastname: Simon