The title compound, C6H12O6, a C-3 position epimer of glucose, was crystallized from an equimolar mixture of d- and l-allose. It was confirmed that d-allose (l-allose) formed β-pyran-ose with a (4) C 1 ((1) C 4) conformation in the crystal. In the crystal, molecules are linked by O-H⋯O hydrogen bond, forming a three-dimensional framework. The cell volume of the racemic β-d,l-allose is 739.36 (3) Å(3), which is about 10 Å(3) smaller than that of chiral β-d-allose [V = 751.0 (2) Å(3)].
Keywords: O—H⋯O hydrogen bonding; crystal structure; racemic compound; rare sugar.