A2TiF5·nH2O (A=K, Rb, or Cs; n=0 or 1): Synthesis, structure, characterization, and calculations of three new uni-dimensional titanium fluorides

Three new uni-dimensional alkali metal titanium fluoride materials, A2TiF5·nH2O (A=K, Rb, or Cs; n=0 or 1) have been synthesized by hydrothermal reactions. The structures of A2TiF5·nH2O have been determined by single-crystal X-ray diffraction. The Ti4+ cations have been reduced to Ti3+ during the synthesis reactions. All three A2TiF5·nH2O materials contain novel 1-D chain structures that are composed of the slightly distorted Ti3+F6 corner-sharing octahedra attributable to the Jahn–Teller distortion. The coordination environment of the alkali metal cations plays an important role to determine the degree of turning in the chain structures. Complete structural analyses, Infrared and UV–vis diffuse reflectance spectra, and thermal analyses are presented, as are electronic structure calculations.

Ball-and-stick and polyhedral representations for (a) β-K2TiF5 and (b) Rb2TiF5·H2O or Cs2TiF5·H2O with the K+ and Rb+ (or Cs+) coordination environment emphasized.Figure optionsDownload as PowerPoint slideResearch highlights
► Synthesis, structure, characterization, and calculation of new titanium fluorides.
► Study of reduction of starting Ti4+ cations to Ti3+ by DMF.
► Novel 1-D chain structures with Jahn–Teller distorted TiF6 octahedra.