Certain radicals attached to the carbon atom of the functional group will produce certain esters. For example, in a one-carbon ester, the carbon in the functional group is used as the one carbon. A single hydrogen atom is attached to the carbon atom in the functional group to complete the bonding requirements. A one-carbon ester uses the alternate name for one carbon, which is "form"; esters end in "ate," so the name of a one-carbon ester is formate.