JON BAUGH / SCIENCE PHOTO LIBRARY JON BAUGH / SCIENCE PHOTO LIBRARY
Animation of a model of a molecule of sulfur trioxide (SO3), showing its electrostatic potential surface as a coloured layer above the atoms. Sulfur trioxide is a symmetrical molecule with three oxygen atoms (red) arranged in a planar equilateral triangle around a central sulfur atom (yellow). As the molecule is perfectly symmetrical, it has no dipole moment and is not polar. Compare this with the ammonia molecule in clip K004/3634. Here, red areas have a slight negative charge, blue areas a slight positive charge. This arises as the oxygen atoms are more electronegative than the sulfur atom, so attract negatively-charged electrons more strongly.
Model release not required. Property release not required.