Single crystals of Ba₂Nb₃S₈I have been grown using iodine-vapor transport in fused-quartz tubes. The crystals form as flakes with typical areas of 5–10 mm² and thicknesses of 5–11 μm. The crystal structure was determined using single-crystal x-ray diffraction with the aid of an APEX II CCD diffractometer. The structure shows trigonal symmetry with space group P31c and lattice parameters a = b = 10.0156(5) Å and c = 25.1414(15) Å. Compositional analysis via x-ray spectroscopy confirms the presence of iodine. Superlattice reflections are evident in x-ray precession images. Measurements of the electrical resistivity reveal a metallic temperature dependence and superconductivity near 1 K. Polycrystalline samples of Ba₂Nb₃S₈I were made in order to have samples large enough for other bulk physical properties measurements. Magnetic susceptibility reveals antiferromagnetism below 275 K. The coexistence of antiferromagnetism and superconductivity is surprising. Specific heat measurements reveal the electronic coefficient γ = 3.95(66) mJ/mol K². The jump in the specific heat at the superconducting transition temperature $T_{\text{c}}$ ($\text{Δ}C/\gamma T_{\text{c}}$ = 1.4(2)) and the energy gap associated with the superconducting state ($E_{\text{g}}$ = 0.405(17) meV) agree well with BCS theory.

Ba ₂ Nb ₃ S ₈ I的单晶已经通过在熔融石英管中的碘蒸气传输来生长。该晶体形成为具有5-10毫米典型地区薄片²和5-11的厚度 μ米。借助于APEX II CCD衍射仪，使用单晶X射线衍射测定晶体结构。该结构显示具有空间群P31c和晶格参数a  =  b  = 10.0156（5）Å和c的三角对称 = 25.1414（15）Å。通过X射线光谱的组成分析证实了碘的存在。超晶格反射在X射线进动图像中很明显。电阻率的测量显示出金属温度依赖性和1 K附近的超导性。制备Ba ₂ Nb ₃ S ₈ I的多晶样品，以使样品大到足以进行其他体积物理性质测量。磁化率表明在275 K以下具有反铁磁性。反铁磁性和超导性并存是令人惊讶的。比热测量显示电子系数γ  = 3.95（66）mJ / mol K ²。超导转变温度下比热的跃变${Ť}_{\text{C}}$ （$\text{Δ}C/\gamma {Ť}_{\text{C}}$ = 1.4（2））和与超导状态相关的能隙（$E_{\text{G}}$ = 0.405（17）meV）与BCS理论非常吻合。