Diamagnetic sulfide Ba3Sc2S6 – With infinite [ScS6/2] chains as structural element

The sulfide Ba 3 Sc 2 S 6 was synthesized by the conventional high-temperature solid-state technique in an inert atmosphere, utilizing sealed silica ampules with low internal pressure of Ar gas. The crystal structure was determined by single crystal X-ray diffraction and can be described by a trigonal crystal lattice with rhombohedral symmetry, R 3 ‾ c (No. 167), with powder diffraction unit cell parameters a = 12.0402(1) Å and c = 13.3893(2) Å. The compound crystallizes with the K 4 CdCl 6 -type structure, which has been used to describe homologous sulfides. This crystal structure shares features with the 2H-perovskites but contains infinite 1D chains, Niggli notation [ ScS 6 / 2 ] ∞ 1 , consisting of alternating, distorted octahedra and trigonal prisms connected by face-sharing. Ba 3 Sc 2 S 6 is diamagnetic, as determined from magnetic susceptibility measurements. UV–Vis spectroscopy data suggest a direct bandgap of about 2.88 eV. Further, DFT calculations reveal a band gap of about 1.8 eV and 2.9 eV using the PBE and the HSE06 functional, respectively, of which the latter agrees perfectly with UV–Vis observations. In novel Ba 3 Sc 2 S 6 , diamagnetic Sc 3+ enters two different S-coordination environments. • The novel, diamagnetic, large band gap semiconductor compound Ba 3 Sc 2 S 6 is reported. • Ba 3 Sc 2 S 6 contains Sc 3+ -chains in distorted trigonal prisms and octahedra of S. • This finding emphasizes the coordination flexibility of scandium in solid-state crystals.