The invention relates to zirconium phosphate of H form which is characterized by a ³¹P NMR spectra comprising peaks at -4.7 ppm, -12.8 ppm and -17.0 ppm (all peaks being in a range of 0.5 ppm). Also featured is a Na form of the material. The zirconium phosphate material is characterized by a unique surface area, pore size distribution and surface morphology, as well as by an affinity for NH₄⁺ ions and moisture insensitivity. Also featured is hafnium phosphate characterized by moisture insensitivity. The zirconium phosphate may be amorphous and possess a framework-type structure. The inventive method of making zirconium phosphate includes the steps of heating an aqueous mixture including a zirconium compound and a phosphorous-containing reagent at a temperature of at least 120 C. to form a reaction product, and treating the reaction product with acid at a temperature of at least 60 C.