Conformation and intramolecular hydrogen-bonding in the crystal structure of potassium D-gluconate monohydrate

The D-gluconate ion is found to have the planar, extended carbon-chain conformation in the crystal structure of potassium D-gluconate monohydrate, with an intramolecular hydrogen-bond between 0-2 and 0-4. The D-gluconate ions and water molecules are linked in puckered sheets by a series of intermolecular hydrogen-bonds that involve the water molecules, the carboxylate groups, and pairs of hydroxyl groups. One hydroxyl group in the ion does not form a hydrogen bond. The potassium ions lie between the puckered sheets, with an eight-fold coordination of six D-gluconate groups and two water oxygen atoms. The crystal structure was determined from three-dimensional, CuKα, X-ray diffraction data taken on an automatic diffractometer.