Crystal Structure and Vibrational Spectrum of Thallium(I) Europium(II) Tetrathiophosphate(V), TIEu[PS4

Abstract

AbstractTlEu[PS4] was synthesized from the elements in a sealed quartz ampoule at 1 150 K. The compound forms transparent orange needles, stable in air and moisture. It crystallizes in the orthorhombic system, space group Pnma (No. 62), with cell dimensions a = 12.157(2), b = 6.581(1), c = 8.802(2) Å, Z = 4. The crystal structure consists of discrete [PS4]3− anions interconnected by Tl+ and Eu2+. The tetrahedral [PS4]3− groups are slightly distorted with PS bond lengths in the range 2.028 to 2.043 Å. These tetrahedral anions are arranged in such a way that the sulfur atoms form columns of distorted trigonal S6 prisms along [0 0 1]. The columns are condensed via common edges to puckered layers parallel to (1 0 0). The interlayer region consists of empty distorted half‐cubes and tetrahedral holes, half of them filled by P atoms. The trigonal prisms in the columns are centered alternately by Tl+ and Eu2+. In this way, the structure can be regarded as an ordered superstructure of the InNi2 type, where half of the tetrahedral holes are filled by phosphorus atoms: InInNi4□ ≙ TlEuS4P□. TlEu[PS4] is a centrosymmetric variant of the TlSn[PS4] structure type (space group Pna21). The vibrational spectrum is in accordance with the X‐ray crystal structure, the Raman and infrared vibrations are assigned on the basis of [PS4]3− units with C2v symmetry.