A topographical study on a series of n-vertex (n = 5-7) closo-boranes, closo-carboranes, and closo-silaboranes using electron density (ED) and molecular electrostatic potential (MESP) reveals many interesting features on the molecular structure and reactivity. No B-B bond critical points exist in the equatorial plane for the five vertex cages. The charge density is found to be more on the exterior of the molecule than on the interior. However, all borane anions exhibit localization of ED in the centroid of the cage. The bond polarities are reversed while going from closo-carboranes to closo-silaboranes. But, the reactivity pattern toward electrophiles essentially parallels in both cases. Among borane anions, B5H52- is more prone toward electrophilic attack. Using MESP as a tool, the positional isomer stabilities of various closo-heteroboranes are predicted and found to agree well with experimental results and other theoretical models.