Novel active catalyst compositions comprising a compound or mixture of compounds represented by the formulaSbFXmY4nullma complex of such a compound or mixture of such compounds being represented by the formulaR.SbFXmY4nullmor a combination of such compounds and complexes where in each formula, X is an anionic moiety, Y is an anion or anions resulting from the deprotonation of an active hydrogen-containing compound(s), m is 0 to 3 and R is one or more active hydrogen containing compound acting as molecules of solvation. The catalyst compositions are useful to promote alkoxylation reactions.