short communications
The structure of a tetragonal crystal form of thiostrepton has been solved using the anomalous dispersive effects of five S atoms from high-redundancy data collected to 1.33 Å resolution at the Cu Kα wavelength. Data measured to 1.02 Å resolution with a synchrotron source were used for refinement. Details of the molecular structure, intramolecular and intermolecular interactions are given.