AbstractThe saccharin (o‐sulphobenzoimide) crystal is synthesized and its crystal structure has also been determined. Saccharin, as a ligand, can be coordinated with a metal ion in different modes. The variations of the saccharin molecular structure in different coordination environments are studied. As the saccharin molecule takes part as ligand or anion, its molecule structure will take some obvious changes. The factors of these changes may mostly be due to the coordination environment and hydrogen bond. The effects of different coordinated metal ion and different coordination mode are very smal