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

The title compound, (C(3)H(10)N(2))(2)[AlF(6)]F·3H(2)O, 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 [AlF(6)](3−) octa­hedra, diprotonated propane-1,3-di­amine cations [(H(2)dap)(2+)], free fluoride ions and water mol­ecules of solvation. The Al—F bond lengths in the octa­hedral [AlF(6)](3−) anions range from 1.7690 (19) to 1.8130 (19) Å, with an average value of 1.794 Å. Each [AlF(6)](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 AlF(6) octa­hedra and dications into a three-dimensional framework.