The title salt, Na+·C6H13O9S- [systematic name: sodium (1S,2S,3S,4R,5R)-1,2,3,4,5,6-hexa-hydroxy-hexane-1-sulfonate], is formed by reaction of d-mannose with sodium bis-ulfite (sodium hydrogen sulfite) in water. The anion has an open-chain structure with the S atom and the C atoms of the carbohydrate chain forming an essentially planar zigzag chain in which the absolute values of the torsion angles lie between 173.6 (2) and 179.9 (3)°. The sodium cations are penta--coordinated by O atoms, with one link to a carbohydrate O atom and four to O atoms of sulfonate residues in separate anions, thus creating a three-dimensional network. The carbohydrate anions are arranged in a head (-SO3-) to head (-SO3-) arrangement, thereby forming two parallel sheets linked through coordination to sodium ions, with each sheet containing inter-molecular hydrogen bonds between the anionic residues. Unusually, the double sheets are not connected to neighbouring sets of double sheets, either by ion coordination or inter-molecular hydrogen bonding.
Keywords: crystal structure; d-mannose bisulfite adduct; sodium hydrogen sulfite; sodium metabisulfite.