Heptose

A heptose is a monosaccharide with seven carbon atoms.
They have either an aldehyde functional group in position 1 (aldoheptoses) or a ketone functional group in position 2, 3 or 4 (ketoheptoses). Ketoheptoses have 4 chiral centers, whereas aldoheptoses have 5.
Examples.
There are few examples of seven-carbon sugars in nature, among which are: