Rb₄Zr₃Te₁₆, a one-dimensional zirconium telluride synthesized from molten salt

A new ternary metal telluride, tetrarubidium trizirconium hexadecatelluride, Rb₄Zr₃Te₁₆, has been synthesized through reactions at 698 K using elemental Zr and an Rb₂Te/Te melt as a reactive flux, and characterized by single-crystal X-ray diffraction. Although the structure of this compound is very similar to its Cs₄Zr₃Te₁₆ analogue, the compounds crystallize in different space groups, the former in C_2h⁶ -C2/c and the latter in C_2h⁵ -P2₁/n. Both compounds consist of infinite one-dimensional chains of [Zr₃Te₁₆]_n^4n- separated from each other by Rb⁺ or Cs⁺ cations. Within the chain, each Zr atom is surrounded by eight Te atoms to give a distorted bicapped trigonal prism polyhedron. There are two unambiguous Te-Te single bonds of 2.758 (2) and 2.765 (2) Å, and four longer Te⋯Te interatomic distances in the range of 2.9277 (14)-3.0445 (18) Å that indicate weak interactions between the adjacent Te atoms. Because of the wide range of Te⋯Te interactions, simple formalisms cannot be used to describe the bonding within the chain.