Ethylene glycol is a clear, sweet, slightly viscous liquid that boils at 198 °C (388.4 °F). Its most common use is as an automotive antifreeze. A 1:1 solution of ethylene glycol and water boils at 129 °C (264.2 °F) and freezes at −37 °C (−34.6 °F), serving as an excellent coolant in automotive radiators.