α-Zirconium phenylphosphonate has been synthesised by a reaction between α-zirconium phosphate and molten phenylphosphonic acid. The reaction produces a physical mixture of the ‘pure’ phases of α-zirconium phenylphosphonate and α-zirconium phosphate, with the ratio dependent on the ratio of phenylphosphonic acid to α-zirconium phosphate in the synthesis mixture. Detailed characterization of the reaction products has been carried out by powder X-ray diffraction, high-resolution solid-state 31P NMR spectroscopy, thermogravimetric analysis and FT-IR spectroscopy, and by considering experiments involving the selective intercalation of n-butylamine.