The shape of the ClO3- ion (chlorate ion) is trigonal pyramidal. In a ClO3- ion, there are three oxygen atoms bonded to the central chlorine atom, and there is one lone pair of electrons on the chlorine atom. This arrangement results in a trigonal pyramidal shape, where the three oxygen atoms are located at the corners of a triangular base, and the lone pair occupies the fourth position above the central chlorine atom.