There is provided a method for preparing an acidic solid oxide having a reduced particle density, where the acidic solid oxide comprises a Group IVB metal oxide modified with an anion or oxyanion of a Group VIB metal. An example of this acidic solid oxide is zirconia modified with tungstate. The acidic solid oxide having a reduced particle density is prepared by coprecipitating the Group IVB metal oxide along with the anion or oxyanion of the Group VIB metal in the presence of a salt. This acidic solid oxide is particularly effective as a paraffin isomerization catalyst.