High Pressure Synthesis of the Spin Chain Sulfide Ba9V3S11(S2)2

Abstract The new compound Ba 9 V 3 S 11 (S 2 ) 2 was synthesized using high pressure and high temperature. The single crystal XRD based structure solution and refinement show that it crystallizes in the hexagonal system with the space group P ‐6 c 2 (188) and the lattice parameters a =9.1979(4) Å and c =18.0462(10) Å. Its one‐dimensional structure is related to the high‐pressure phase Ba 9 V 3 Se 15 (Ba 9 V 3 Se 11 (Se 2 ) 2 ) and consists of chains made of face‐sharing VS 6 octahedra running along the c ‐axis. The chains contain two distinct sites of Vanadium with a mixed valence state of V 3+ and V 2+ . The space between the chains, two type of columns, is occupied by disulfides (S 2 ) 2− pairs and isolated sulfide anions S 2− surrounded by Ba 2+ cations. The distributions within the columns are slightly different than in Ba 9 V 3 Se 11 (Se 2 ) 2 making the two compounds not strictly isostructural but analogues with the same symmetry and unit cell. We discuss this phase on the basis of crystallochemical analysis and DFT calculated electronic structure. Assuming a magnetic insulator as found from DFT+ U calculations, we discuss the existence of magnetic clusters within the spin chains.