Carbonyl compounds are a class of organic compounds that contain a carbonyl group, which is a functional group with the formula C=O, composed of a carbon atom double-bonded to an oxygen atom, and it is divalent at the C atom. The carbonyl group is the most important functional group in organic chemistry and is found in aldehydes, ketones, and carboxylic acids. The simplest carbonyl groups are aldehydes and ketones, which are usually attached to another carbon compound/Aldehydes_and_Ketones/Properties_of_Aldehydes_and_Ketones/The_Carbonyl_Group). The carbon and oxygen atoms in the carbonyl group are usually sp2 hybridized and planar/Aldehydes_and_Ketones/Properties_of_Aldehydes_and_Ketones/The_Carbonyl_Group). Carbonyl compounds are polar and have higher melting and boiling points than hydrocarbons containing the same number of carbon atoms and are more soluble in polar solvents such as water. Compounds containing a carbonyl group can enter into a variety of chemical reactions, and nucleophilic reagents are attracted to the carbon atom, whereas electrophilic reagents are attracted to the oxygen atom.