The present invention relates to a process for the preparation of polyether polyols by the reaction of alkylene oxides and compounds containing active hydrogens, in the presence of specific Lewis acid metal compounds as catalysts, novel bis(perfluoroalkylsulfonic acid) compounds of Group 13 of the Periodic Table of the Elements, and to a process for the preparation thereof and the use thereof as catalysts for ring-opening polymerization of cyclic ethers.