Crystal and Electronic Structures of a Chain Vanadium Selenoiodide [V3Se12I2]I3·1/4I2

A crystal of the [V₃Se₁₂I₂]I₃·1/4I₂ vanadium selenoiodide is prepared by a reaction of vanadium, selenium, and iodine at 240 °C. According to the single-crystal XRD data (P2₁/c space group, a = 19.1162(7) Å, b = 13.6844(5) Å, c = 18.1423(6) Å, β = 90.663(2)°, V = 4745.6(3) Å³, T = 150 K, Z = 8), the [V₃Se₁₂I₂]I₃·1/4I₂ structure contains positively charged \([{{\text{V}}_{3}}\text{S}{{\text{e}}_{12}}{{\text{I}}_{2}}]_{\infty }^{+}\) chains composed of {V₃I(Se₂)₃(Se₂I)} linear groups with V⋯V distances of 2.98 Å. The groups are interconnected by μ-(Se₂) and μ-(Se₂I) bridging ligands (one at a time) with a larger V⋯V distance of 3.74 Å. The [V₃Se₁₂I₂]I₃·1/4I₂ structure is characterized by the presence of a Se–Se–I ligand connecting vanadium atoms by the μ-Se₂-κ²,κ¹ type. The calculated bandgap of 0.78 eV indicates that the vanadium selenoiodide possesses semiconducting properties. The crystal structure of [V₃Se₁₂I₂]I₃·1/4I₂ is discussed; the electronic structure and stability of this compound are calculated.