Ba3[LiSbS2(S2)2Cl2]: The first zero-dimensional (0D) lithium metal thioantimonate featuring molecular anions of [LiSbS2(S2)2Cl2]6–

Abstract

The first lithium metal thioantimonate featuring 0D structure, namely Ba3[LiSbS2(S2)2Cl2], has been prepared from a mixture of BaCl2, LiCl, Ba, Sb, and S in an evacuated graphite crucible coated silica tube. The Ba3[LiSbS2(S2)2Cl2] crystallizes in space group C2/m (No. 12) with a ​= ​13.308(9) Å, b ​= ​12.116(7) Å, c ​= ​9.408(6) Å, V ​= ​1425.4(16) Å3 and Z ​= ​4. It adopts a new 0D structure type with unusual discrete clusters of [LiSbS2(S2)2Cl2]6– arranged in a pseudolayer motif extending in ab plane. The Ba2+ cations are located in the interspaces. The molecular anions of [LiSbS2(S2)2Cl2]6– can be best regarded as eight-membered rings built of two LiS2(S2)2 tetrahedra and two disordered SbS2Cl2 teeter-totter polyhedra via corner-sharing. Another notable structural feature is the occurrence of the LiS2(S2)2 tetrahedra which are derived from the LiS4 tetrahedra by substituting two terminal S2− anions with two disulfide [S2]2– units. Disordered SbS2Cl2 teeter-totter polyhedra are derived from the fusing of the two trigonal-pyramidal SbS2Cl units. Moreover, presence of chloride anions in terminal vertexes of SbS2Cl trigonal pyramids as well as Ba-rich ratio may be responsible for ceasing the propagation of Li/Sb/S networks, resulting in the unusual 0D structure in the titled compound. In addion, the density functional theory (DFT) study reveals a direct bandgap of 2.6 ​eV, which can be ascribed to the electronic transitions from the top of valence band dominated by the 3p states of disulfide [S2]2– to the 5d states of Ba atoms and 3p states of disulfide [S2]2–.