AbstractThe X‐ray crystal structure analysis of Na‐sulfadimidine is reported. Crystals are triclinic. Space group P1witha= 5.785(2),b= 11.568(1),c= 12.722(2) Å, α = 70.02(1), β = 78.71(2), γ = 77.73(2)° andZ= 2. Crystal structure was solved by direct method to anR‐value of 0.061 for 2441 unique reflections. It is a type of five‐fold coordination complex of Na where Na atom is surrounded by four oxygen atoms and one nitrogen atom: three oxygen atoms and the nitrogen atom belongs to the sulfonyl moiety from three different sulfadimidine molecules and the fourth oxygen atom belongs to solvent water molecule. The crystal structure is stabilized by hydrogen bonds and van der