Sulfuric and sulfurous acids form a series of esters analogous to those from other acidic materials. The hydrogen of the acid is replaced by a carbon‐containing group. Because two hydrogens are present in the sulfur‐based acids, there are two series of esters. Replacement of one hydrogen results in an acid ester. If both hydrogens are replaced, whether with the same, with different, or with bifunctional substituents, symmetrical and unsymmetrical diesters form. Dimethyl sulfate, diethyl sulfate, and long‐chain monoalkyl alkali metal sulfates are the compounds of practical interest. Dialkyl sulfates have been used to introduce a methyl or ethyl group into a wide variety of organic compounds. The long‐chain monoalkyl hydrogen sulfates, in the form of their alkali metal or alkylammonium salts, are valuable as surface‐active agents and are used commercially. The short‐chain monoalkyl hydrogen sulfates are intermediates in commercial conversion routes from olefins to alcohols.