Ovchinnikov Alexander, Bobev Svilen
Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, United States.
Department of Materials and Environmental Chemistry, Stockholm University, Stockholm, Sweden.
Front Chem. 2020 Jan 10;7:909. doi: 10.3389/fchem.2019.00909. eCollection 2019.
The flux growth method was successfully employed to synthesize millimeter-sized single crystals of the ternary barium vanadium pnictides BaVAs ( ≈ 0.02) and BaVSb ( ≈ 0.36), using molten Pb and Sb, respectively. Both compositions crystallize in space group 3 and adopt a structure similar to those of the barium titanium pnictides BaTi ( = Sb, Bi), yet with a subtly different disorder, involving the pnictogen and barium atoms. Attempts to obtain an arsenide analog of BaTi using a Pb flux technique yielded binary arsenides. High-temperature treatment of the elements Ba, Ti, and As in Nb or Ta tubes resulted in side reactions with the crucible materials and produced two isostructural compositions BaTi As ( = Nb, Ta; ≈ 4), representing a new structure type. The latter structure displays -type metal clusters comprised of statistically distributed Ti and atoms ( = Nb, Ta) with multi-center and two-center bonding within the clusters, as suggested by our first-principle calculations.
采用助熔剂生长法，分别以熔融的铅和锑为助熔剂，成功合成了毫米级的三元钡钒磷化物BaVAs（≈0.02）和BaVSb（≈0.36）单晶。这两种化合物均结晶于空间群3，其结构与钡钛磷化物BaTi （ = Sb，Bi）相似，但在涉及磷族元素和钡原子的无序状态上略有不同。尝试使用铅助熔剂技术获得BaTi 的砷化物类似物，结果得到了二元砷化物。在铌或钽管中对元素钡、钛和砷进行高温处理，导致与坩埚材料发生副反应，并生成了两种同构化合物BaTi As（ = Nb，Ta；≈4），代表一种新的结构类型。正如我们的第一性原理计算所表明的，后一种结构显示出由统计分布的钛和 原子（ = Nb，Ta）组成的 - 型金属簇，簇内存在多中心和双中心键合。
