For each molecular geometry, list the number of total electron groups, the number of bonding groups, and the number of lone pairs on the central atom. With fewer 90° LP–BP repulsions, we can predict that the structure with the lone pair of electrons in the equatorial position is more stable than the one with the lone pair in the axial position. Transition Metals and Coordination Compounds 3h 14m. With two bonding pairs and three lone pairs, I 3 has a total of five electron pairs and is designated as AX 2 E 3. To minimize repulsions, the groups are directed to the corners of a trigonal bipyramid. Multiple bonds (double or triple bond) are regarded as one electron group for VSEPR purpose. If we place it in the axial position, we have two 90° LP–BP repulsions at 90°. There are five electron groups about the central atom in I 3, two bonding pairs and three lone pairs. For VSEPR purpose, the terms shape and geometry are interchangeable electron pair and electron group are also interchangeable. However, because the axial and equatorial positions are not chemically equivalent, where do we place the lone pair? If we place the lone pair in the equatorial position, we have three LP–BP repulsions at 90°. In molecular shape (molecular geometry) you treat the electron’s lone pairs and the bonds as two different and separate things. We designate SF 4 as AX 4E it has a total of five electron pairs.
