Animation of a mixture of ethanol (alcohol) and hexane molecules, showing their miscibility. Hexane is an alkane, a chain of six carbon atoms with attached hydrogen. Ethanol contains a two-carbon backbone and a hydroxyl group. The hydroxyl group is polar, featuring partial separation of charge, with a slight positive charge (blue) on the hydrogen and a negative charge (red) on the oxygen. The carbon backbones, however, have no separation of charge. These interact with each other through van der Waals forces (green glow), a weak interaction due to transient arrangements of the electron clouds surrounding the atoms. Although weak, the interactions are enough to allow the ethanol to mix completely with the hexane. The polar hydroxyl group on the ethanol also allows it to interact with other polar solvents, like water, as can be seen in clip K004 5234.