Crystalline ZrPO4Cl(CH3)(2)SO was prepared by direct precipitation in the presence of oxalic acid as a zirconium complexing agent. The structure of ZrPO4Cl(CH3)(2)SO, refined with the Rietveld method using X-ray powder diffraction data, was confirmed to be close to that of the compound prepared using gamma-zirconium phosphate as a precursor. Chloride anions directly bonded to zirconium were found to act as weak ligands; this made possible their replacement with other monodentate anionic ligands. The preparation and a preliminary characterization of a series of inorganic derivatives obtained by topotactic replacement of Cl with OH, Br, MSO4 (M = H, NH4, Na), NaMoO4, and HCrO4 anions is reported, The possibility of replacement of chloride also with organic anions, such as alkoxides and carboxylates, and the possibility of substituting also dimethyl sulfoxide with other neutral ligands, as shown by preliminary study, makes ZrPO4Cl(CH3)(2)SO a useful and very flexible precursor for materials chemistry.