The title compound, C12H24NO10+·Cl−·H2O, (I), crystallizes in the monoclinic space group P21 and exists as a monohydrate of a monosubstituted ammonium chloride salt, with the reducing carbohydrate portion existing exclusively as the α-pyranose tautomer. The glycosidic bond geometry in (I) is stabilized by an intramolecular hydrogen bond and is close to that found in crystalline α-lactose. All heteroatoms except glucopyranose ring O4 participate in an extensive hydrogen-bonding network, which propagates in all directions in the crystal structure of (I).
