The matlockite-type praseodymium(III) oxide bromide PrOBr

The crystal structure of the praseodymium(III) oxide bromide, PrOBr, can be best described with layers of agglomerated square anti­prisms [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 [Image: see text] m2 and have four Pr(3+) cations as neighbours, defining a tetra­hedron.