All reagents were from commercial sources and used without
further purification. Antimony(III) trichloride (2 mmol, 456 mg)
and N-(2-hydroxyethyl)piperazine (2 mmol, 260.4 mg) were dissolved in a concentrated HCl (6 M) solution in the presence of ethanol (10 mL) in a stoichiometric ratio. The resulting aqueous
solution was then kept at room temperature (298 K). Colorless parallelepiped crystals of [C6H16N2O]SbCl5 were obtained by slow
evaporation (Yield: 65%) of good quality for single X-ray diffraction
analysis.