A thioether is a functional group in organosulfur chemistry with the connectivity C–S–C as shown on right. Like many other sulfur-containing compounds, volatile thioethers have foul odors. A thioether is similar to an ether except that it contains a sulfur atom in place of the oxygen. The grouping of oxygen and sulfur in the periodic table suggests that the chemical properties of ethers and thioethers are somewhat similar, though the extent to which this is true in practice varies depending on the application.