α-D,l-Sorbose

The racemic title compound, C6H12O6, consisting of C-4 epimers of psicose, was crystallized from an aqueous solution of an equimolar mixture of d- and l-sorboses. It was confirmed that d-sorbose (or l-sorbose) formed α-pyranose with a 4C1 (or 1C4) conformation where the anomer position was designated as carbon-1. The asymmetric unit comprises two crystallographically independent molecules. In the crystal, molecules are linked by O—H...O hydrogen bonds, forming a three-dimensional framework. The unit-cell volume of the title racemic α-d,l-sorbose is 1450.86 (6) Å3 (Z = 8), which is about 41 Å3 smaller than that of twice the amount of chiral α-l-sorbose [V = 745.942 Å3 (Z = 4)].