title: Framework structures of interconnected layers in calcium iron arsenides.
abstract: The new calcium iron arsenide compounds Ca(n(n+1)/2)(Fe(1-x)M(x))(2+3n)M'(n(n-1)/2)As((n+1)(n+2)/2) (n = 1-3; M = Nb, Pd, Pt; M' = □, Pd, Pt) were synthesized and their crystal structures determined by single-crystal X-ray diffraction. The series demonstrates the structural flexibility of iron arsenide materials, which otherwise prefer layered structures, as is known from the family of iron-based superconductors. In the new compounds, iron arsenide tetrahedral layers are bridged by iron-centered pyramids, giving rise to so far unknown frameworks of interconnected FeAs layers. Channels within the structures are occupied with calcium and palladium or platinum, respectively. Common basic building blocks are identified that lead to a better understanding of the building principles of these structures and their relation to CaFe4As3.
authors.affiliation: Department Chemie, Ludwig-Maximilians-Universität München , Butenandtstrasse 5-13 (Haus D), 81377 München, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Stürzer
authors.forename: Christine
authors.initials: C
authors.lastname: Hieke
authors.forename: Catrin
authors.initials: C
authors.lastname: Löhnert
authors.forename: Fabian
authors.initials: F
authors.lastname: Nitsche
authors.forename: Juliane
authors.initials: J
authors.lastname: Stahl
authors.forename: Christian
authors.initials: C
authors.lastname: Maak
authors.forename: Roman
authors.initials: R
authors.lastname: Pobel
authors.forename: Dirk
authors.initials: D
authors.lastname: Johrendt