Molecular formulas that are also empirical formulas represent compounds in which all atoms of the same element are bonded in the same way. Examples include methane (CH₄) and water (H₂O), in which all carbon atoms are bonded to four hydrogen atoms and all hydrogen atoms are bonded to one oxygen atom, respectively. In contrast, compounds with different molecular formulas but the same empirical formula are called isomers. For instance, both ethanol (C₂H₆O) and dimethyl ether (C₂H₆O) have the same empirical formula (CH₃O), but they have different molecular structures and properties.