Ethanol's chemical formula is C2H6O. This chemical formula can also be written as CH3CH2OH or C2H5OH. It is made of nine atoms that include two carbon (C) atoms, six hydrogens (H) atoms, and one oxygen (O) atom. Its chemical structure is illustrated in the following picture. Here, there is a methyl group (which is the CH3-), a methylene group (which is the -CH2-), and a hydroxyl group (which is the -OH) in the chemical structure.