Notizen: Die Kristallstruktur von [(CH3)4N]FeF4 · H2O mit einem di(µ-fluoro)-verbrückten [Fe2F8(H2O)2]2–-Anion / Crystal Structure of [(CH3)4N]FeF4 · H2O with a Di(μ-fluoro)-Bridged [Fe2F8(H2O)2]2- Anion

Abstract

Single crystals of [(CH3)4N]FeF4·H2O have been prepared from aqueous HF solution. The crystal structure was determined by X-ray diffraction: space group P1̄, Z = 2 (or 1 dimeric unit), a = 705.7(5), b = 818.5(8), c = 915.2(12) pm, α = 65.46(10)°, β = 82.90(9)°, γ = 72.76(7)°, R/wR = 0.047/0.021. The structure consists of centrosymmetrical dimeric anions [Fe2F8(H2O)2]2- with fluorine double bridges and is isotypic with [(CH3)4N]VOF3 · H2O. Intramolecular H-bonds are found between the axial water and fluoride ligands. By additional strong intermolecular H-bonds (O ··· F 258 pm) the anions are connected to form infinite parallel chains between which the TMA cations are located. [(CH3)4N]AlF4 · H2O is shown to be isotypic.