Cyclic terpenoid onium salts, their preparation and uses

A process for cyclizing an acyclic terpenoid group of an onium salt selected from a quaternary ammonium salt and a phosphonium salt, where said terpenoid group is a neryl group or a geranyl group, which comprises maintaining an acidic aqueous solution of said onium salt at a temperature of at least about 80.degree. C. until said acyclic terpenoid group cyclizes, there being at least about 1.1 equivalents of acid per equivalent of said onium salt.