An electron density study of sodium sulfanilate dihydrate at 78 K

The crystal structure of sodium sulfanilate dihydrate has been redetermined from single-crystal X-ray data collected at 78 K. Separate least-squares refinements were performed on the low-order data, the high-order data and the entire data set. The nonplanarity of the amino group has been reconfirmed. Difference density maps, based on the atomic parameters from the high-order refinement, are interpreted in terms of bonding effects. An analysis of the charge distribution led to net charges of -0.37 (4), +0-07 (4) and +0.15 (4) e for the sulfanilate group, Na atom and hydrate molecules respectively.