title: Y(21)I(18)C(14)B(7): Synthesis, Average Structure, and Structural Misfit.
abstract: The new compound Y(21)I(18)C(14)B(7) was prepared from YI(3), Y, C, and B at 1450 K. The average crystal structure was determined from single-crystal X-ray data. The structure consists of pseudoorthorhombic twisted metal atom double layers containing quasi-molecular CBC units. These are sandwiched by pseudohexagonal iodine layers. Owing to the symmetry and metric misfit the structure must be described with a large triclinic unit cell (space group P&onemacr;, a = 10.660(2) Å, b = 15.546(3) Å, c = 18.416(3) Å, alpha = 82.49(2) degrees, beta = 85.01(2) degrees, gamma = 82.92(2) degrees, Z = 2), which is probably only a good space-averaged approximation. Significant deviations from the averaged structure are indicated by unusual displacement parameters and the results of high-resolution electron microscopy.
authors.affiliation: Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Oeckler
authors.forename: Viola
authors.initials: V
authors.lastname: Duppel
authors.forename: Hansjürgen
authors.initials: H
authors.lastname: Mattausch
authors.forename: Arndt
authors.initials: A
authors.lastname: Simon