α-Hydroxyl α-toluenephosphonic acid,being similar to mandelic acid in structure,has been found to be a highly specific and sensitive reagent for zirconium.It is easily prepared and is very soluble in water.From 4 N hydrochloric acid medium,the reagent precipitates immediately zirconium(hafnium),titanium,niobium and tantalum only.However,the latter three can be masked by hydrogen peroxide.Thorium is only slowly and partially precipitated at this acidity and is coprecipitated with zirconium.From 3-4 N hydrochloric acid media,zirconium is quantitatively precipitated with only two-fold excess of the precipitant while large excess is required in the case of mandelic acid.