Crystal structure of bis(propane-1,3-diammonium) hexafluoridoaluminate fluoride trihydrate

The title compound, (C3H10N2)2[AlF6]F·3H2O, was obtained using the solvothermal method with aluminium hydroxide, HF and propane-1,3-diamine as precursors in ethanol as solvent. The structure consists of isolated [AlF6]3− octahedra, diprotonated propane-1,3-diamine cations [(H2dap)2+], free fluoride ions and water molecules of solvation. The Al—F bond lengths in the octahedral [AlF6]3− anions range from 1.7690 (19) to 1.8130 (19) Å, with an average value of 1.794 Å. Each [AlF6]3− anion is surrounded by three water molecules and by six diprotonated amine cations. The `free' fluoride ion is hydrogen bonded to four H atoms belonging to four dications and has a distorted tetrahedral geometry. The three water molecules are connected by hydrogen bonds, forming trimers that connect the AlF6 octahedra and dications into a three-dimensional framework