Cadmium and lead(II) acesulfamate, Cd(C₄H₄NO₄S)₂ · 2H2O and Pb(C₄H₄NO₄S)₂, were prepared by the reaction of acesulfamic acid and the respective metal carbonates in aqueous solution, and characterized by elemental analysis. Their crystal structures were determined by single crystal X-ray diffraction methods. The Cd(II) compound crystallizes in the monoclinic space group P2₁/c with Z = 4 and the corresponding Pb(II) salt in the triclinic space group P1̅ with Z = 2. In both salts, acesulfamate acts both as a bi-dentate ligand through its nitrogen and carbonyl oxygen atoms and also as a mono-dentate ligand through this same oxygen atom, giving rise to polymeric structures; in the Pb(II) salt the ligand also binds the cation through its sulfoxido oxygen atoms. The FTIR spectra of the compounds were recorded and are briefly discussed. Some comparisons with other related acesulfamate and saccharinate complexes are made.Facultad de Ciencias ExactasCentro de Química InorgánicaInstituto de Física La Plata