(rotates it counterclockwise).

The - and - prefixes are also used with other monosaccharides, to distinguish two particular stereoisomers that are mirror-images of each other. For this purpose, one considers the chiral carbon that is furthest removed from the C=O group. Its four bonds must connect to -H, -OH, -CH₂(OH), and the rest of the molecule. If the molecule can be rotated in space so that the directions of those four groups match those of the analog groups in -glyceraldehyde's C2, then the isomer receives the - prefix.