First evidence for the existence of hexafluoroantimonic(v) acid.

By reacting IPr⋅InBr3 with AgSbF6 in dichloroethane at room temperature, we could obtain single crystals comprising [{(IPr⋅InBr3 )(Ag⋅(CH2 Cl)2 )}2 ][SbF6 ]2 (1) and two identical HSbF6 units. It is presumed that the reaction gave rise to [IPr⋅InBr3-x ][SbF6 ]x (x=1, 2, or 3) which reacted with adventitious water to give HSbF6 and [IPr⋅InBr3-x (OH)][SbF6 ]x-1 . The experiment was reproduced at 60 °C, eventually leading to the indium hydroxide [{IPr⋅In(OH)0.5 (H2 O)4.5 }2 ][SbF6 ]5 (2).