Carbohydrates are generally characterized by the formula (CH₂O)n where n is usually 6. This formula provides this class of compounds with their name, the carbohydrates. But this is misleading, since the bonding arrangement is not a carbo, or carbon atom, bonded to a hydrate, but usually a carbon atom bonded to both hydrogen and a hydroxyl group. Even this is still somewhat misleading. A better definition of carbohydrates is to say that they are polyhydroxy, aldehydes and ketones and their derivatives.

Some important common ones are shown here. (These are also shown in Example 8 in your work book.