Lithium aspirinate hemihydrate

The title compound {systematic name: catena‐poly[lithium(I)‐μ₃‐acetylsalicylato‐hemi‐μ₂‐aqua]}, {[Li(C₉H₇O₄)]·0.5H₂O}_n, is the hemihydrate of the lithium salt of aspirin. The carboxylate groups and water molecules bridge between Li atoms to form a one‐dimensional coordination chain composed of two distinct ring types. The water O atom lies on a twofold axis. Hydrogen bonding between water donors and carbonyl acceptors further links the coordination chains to form a sheet structure.