Animation of the structure of a molecule of sulfur dioxide (SO2). This molecule has a bent geometry, with two oxygen atoms (red) forming a shallow V with a central sulfur atom (yellow). This geometry is adopted as the oxygen atoms repel each other, but the sulfur atom also contains a lone pair of electrons, which repels the oxygens slightly more than they do each other. The black arc shows the angle between the atoms. See clip K004 3560 for the molecule showing the lone pair, and K004 3552 for the molecule without this angle measurement.