Struktur und elektrochemische Untersuchung von Nb3Cl8

Structure and Electrochemical Study of Nb₃Cl₈ The compound Nb₃Cl₈ was synthesized from NbCl₅ and niobium metal in a sealed quartz ampoule at 700 °C. Single crystals, obtained from LiCl melt were used for X‐ray structure determination (space group P 3 m1, Z = 2, lattice parameters a = b = 672.95(7) pm, c = 1223.2(2) pm (at 100 K), R1 = 0.029, wR2 = 0.064 for all independent reflections). Electrical resistivity measurements are reported. Electrochemical intercalation of lithium into the structure of Nb₃Cl₈ was studied.     

Die Leiterstruktur von LiNb6Cl19

The Ladder Structure of LiNb₆Cl₁₉ LiNb₆Cl₁₉ was obtained from a solid state reaction of Nb powder, NbCl₅, and Li₂C₂ at 530 °C. The structure was refined by single‐crystal X‐ray diffraction (space group Pmma (No. 51), Z = 2, a = 2814.6(1) pm, b = 687.35(5) pm, c = 641.39(3) pm). It contains edge and face bridging [NbCl₆] octahedra forming the motif of a ladder. The parallel alignment of ladders yields a one‐dimensional structure, with lithium ions occupying voids. Each ladder combines characteristic fragments from the niobium chloride structures NbCl₄, A₃Nb₂Cl₉ (A = Rb, Cs), and Nb₃Cl₈. The arrangement of niobium atoms in LiNb₆Cl₁₉ appears to be similar with trigonal niobium clusters obtained in the structure of Nb₃Cl₈. The electronic structures of niobium clusters in Nb₃Cl₈ and LiNb₆Cl₁₉ are compared with each other.     

Synthesis and Spectroscopic Characterization of Potassium Polyfluoroalken‐1‐yltrifluoroborates

The potassium fluoroborates K[RCF=CFBF₃] (R = F, Cl (cis‐/trans‐mixture), trans‐C₄F₉, cis‐C₂F₅, cis‐C₆F₁₃, trans‐C₄H₉, trans‐C₆H₅) were prepared by fluoridation (methoxide‐fluoride substitution with K[HF₂]) of RCF=CFB(OMe)₂ and Li[RCF=CFB(OMe)₃] which were obtained from RCF=CFLi and B(OMe)₃. The K[RCF=CFBF₃] salts were characterized by their ¹H, ¹¹B, ¹⁹F NMR and IR spectra.