How to Draw Orbital Overlap Diagrams

Science Learning Center

The Key

• Make sure that you follow the exact same steps each time.

• It’s too easy to miss something if you do the drawings with a different order to the steps.

• You can change the order from what we show you here, but whatever order you use, use the same each tme.

Step 1

• Draw the atoms in the same positions as the Lewis Dot Structure.

• Example:

C

HH

O

Step 2

• We’ll be focusing on all the orbitals involved in sigma bonds (the first bond between atoms) and lone pair electrons first.

• Draw the s orbitals for H and the hybrid orbitals for all the other atoms.

• Remember that 2 groups of electrons = sp, 3 grp = sp2, 4 grp = sp3.

C

HH

O

Step 3

• Label all the orbitals.• Add electrons to all the

orbitals. Note that the electrons should be drawn as half arrows, not as arrows like is shown here. One should be pointing up and one should be pointing down.

• Add sigma symbol to all the overlaps.

C

HH

OSP2

SP2 SP2

SP2

SP2SP2

SS

s

ss

Step 4• Now we will deal with the pi bond. Pi

bonds are used to form any bond beyond the first bond (so double and triple). Recall the pi bonds are made from p orbitals. Because the C and O are sp2 hybridized, they each have a p orbital that can be used to form the pi bond.

• Draw one p orbital for each atom involved in the pi bond. Only label one of the orbs, because there is only one p on each atm.

• Add electrons one pointing up to one p orbital and one pointing down to the other p orbital.

• Show the connection by drawing a line from lobe to lobe.

• Add pi symbol to all the overlaps.

C

HH

OSP2

SP2 SP2

SP2

SP2SP2

SS

s

ss

P

P

Step 5

• Draw the bond angle between any three consecutive atoms. The angle is whatever number goes with the hybridization of the central atom. In this case, that is sp2 = 120 degrees.

C

HH

OSP2

SP2 SP2

SP2

SP2SP2

SS

s

ss

P

P