Product Name Dimethyl sulfoxide CAS 67-68-5 Molecular Formula C2H6OS Molecular Weight 78.13 Appearance Colorless transparent liquid Melting Point 18.4 °C Boiling Point 189 °C(lit.) Density 1.100 g/mL at 20 °C Flash Point 192 °F Vapour pressure 0.42 mm Hg ( 20 °C) Vapor density 2.7 (vs air)