Methanol. Molecular model of the organic compound and alcohol methanol (C.H4.O), also known as methyl alcohol. This compound is a light, volatile colourless and flammable liquid. It is used as an antifreeze, solvent, fuel and as a denaturant for ethanol (added to make the ethanol unfit for human consumption). Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white) and oxygen (red).