title: The matlockite-type praseodymium(III) oxide bromide PrOBr.
abstract: The crystal structure of the praseodymium(III) oxide bromide, PrOBr, can be best described with layers of agglomerated square anti-prisms [PrO(4)Br(4)](9-). These slabs are stacked along the c axis and linked via two different secondary contacts between Pr(3+) and Br(-). The Pr(3+) cations occupy the Wyckoff site 2c with 4mm symmetry and carry four O(2-) anions as well as four primary Br(-) anions, yielding a coordination number of 8. While the Br(-) anions exhibit the same site symmetry as the Pr(3+) cations, the oxide anions are located at the Wyckoff position 2a with site symmetry [Formula: see text]m2 and have four Pr(3+) cations as neighbours, defining a tetra-hedron.
authors.affiliation: Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart,  Germany.
authors.forename: Pia
authors.initials: P
authors.lastname: Talmon-Gros
authors.forename: Christian M
authors.initials: CM
authors.lastname: Schurz
authors.forename: Thomas
authors.initials: T
authors.lastname: Schleid