Etficiency of Orbital Overlap: Visual Demonstration Sigma bonds arestrongest when they involve the overlapof twoatomic orbitals along the internuclear axis, in an "end-on" manner. Simple models can be made to visually drmmstrate this. Hybrid orbitals of generalized shape can be cut f r m transpnrent sheets of polarized plastic. For a pair of hvbrid orbitals. the axis of oolari,atim ofthe olasttcrhould he onsittoned so as todiffer bv 90° fur thp tw,, urhitals. A "d~mnle"can be made in the olastirat the nucleus location1 for&easa pivot; a thumbtack head can he cemented in place o r e small hole can be drilled through which a nail or pin is inserted. Large size orbitals are useful in large lecture halls for display against light boxes. Smaller orbitals would be appropriate on an overhead projector. For a chosen internuclear distance, maximum overlap clearly occurs when the orbitals "point" directly at one another, along the internuclear axis. Because of the palarizers, the region of overlap will not only have greatest "area" but will also have highest optical density for thisgeometry. As the orbitals are rotated away from theaxis (at constant internuclear distance) both the amount of overlap ("ares") and optical density of the overlap region are seen to decrease. This visually reinforces the concept that maximum and mmt efficient overlap for tw
