The quintessential chalcogen-nitrogen compound tetrasulfur tetranitride, S4N4, was first detected by Gregory in 1835 just ten years after the discovery of benzene. Its unusual structure, like that of benzene, was not elucidated for over 100 years. The application of diffraction techniques revealed the unusual cage arrangement with two weak cross-ring sulfurâ"sulfur interactions. The details of the electronic structure of this fascinating molecule are still a matter of debate today. Pioneering wo