Chemistry · Chapter 8

Orbital Overlap: Where a Bond Settles

Drag the two hydrogen atoms closer and farther apart. The shaded lens is the shared space their 1s orbitals occupy. Watch the overlap and the energy change as you move.

The model top: the orbitals · bottom: the energy

H H 74 pm shared space 0 distance between the nuclei (pm) energy (kJ/mol) the gold dot is where you are now

What you are seeing

Move the slider to begin.

Controls

74pm apart bonded

Live numbers

Overlap S (1 = on top of each other)0.75
Energy−436 kJ/mol
Energy per bond7.24e−19 J
Compared with 74 pmat the bottom

The overlap uses the real 1s formula. The energy uses a Morse curve set to the measured H2 values of 74 pm and 436 kJ/mol.

Why the dip exists
A tug of war
Pulling the atoms together lets each nucleus grab the other atom's electron. That lowers the energy. Pushing them too close makes the two nuclei shove each other. That raises it. The bottom of the dip is the bond length.