We can apply VSEPR theory systematically to the interior atoms of a larger molecule to determine its overall shape. For example, the organic molecule glycine has four interior atoms. Remember that interior atoms are bonded to two or more other atoms. We can apply VSEPR theory to determine the molecular geometry around each of the four interior atoms. For nitrogen, we have three bonding groups and one lone pair, so the molecular geometry is trigonal pyramidal. For the left-most carbon, we have four bonding groups and no lone pairs, so the molecular geometry is tetrahedral. For the right-most carbon, we have three bonding groups and no lone pairs, so the molecular geometry is trigonal planar. And for the oxygen atom, we have two bonding groups and two lone pairs, so the molecular geometry is bent. Applying the molecular geometry at each atom allows us to envision the structure three-dimensionally. We can apply VSEPR theory at each interior atom to as large of a molecule as we want. For example, let's determine the molecular geometry at each of the four atoms in red in this organic molecule. For the carbon on the left, we have three bonding groups and no lone pairs; this produces a trigonal planar geometry. In fact, all of the carbons in the fused rings have a trigonal planar geometry, so these rings are flat, having all of the atoms on the same plane. Next, we can look at the oxygen atom. It has two bonding groups and two lone pairs, so it has a bent molecular geometry. For the nitrogen atom, it has three bonding groups and one lone pair, so it has a trigonal pyramidal molecular geometry. And for the carbon on the right, it has four bonding groups and no lone pairs, so it has a tetrahedral molecular geometry. Determining the molecular geometry at each of the interior atoms allows us to piece together the overall structure of the molecule propranolol.