The molecular geometry of C2H6 (ethane) is tetrahedral.

Hybridization: Ethane

NSF ATE DUE#1601612

C2H6

 

H

Hybridization State

Tetrahedral

C

C2H6

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Ground State

Hydrogen

1H

p, 1

 [He]

 [He] 2s2 2p2

p, 2

p, 3

6C

sp3

s

Hybrid Orbital

As shown on the Periodic Table, Hydrogen has a Ground State of 1s1

As shown on the Periodic Table, Carbon has a Ground State of [He] 2s22p2   as represented by this orbital diagram.

3

4

1

To make CH4, we need 4 singly occupied orbitals to bond.

2

CH4 bonds should all be equal, but remember that s bonds are stronger than p bonds, so nature has to do something to make the orbitals uniform. That something is hybridization.  

Now that we have 4 uniform, singly occupied orbitals, we can bring in H to make Methane.

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 [He] 2s2 2p2

As shown on the Periodic Table, Carbon has a Ground State of [He] 2s22p2 as represented by this orbital diagram.

  2p2 2s2 [He]

Carbon

6C

 [He]

 [He] 

Notice there are only two singly occupied orbitals for bonding for each Carbon.

[He]

Promotion State

To make C2H4, we need 4 singly occupied orbitals to bond for each Carbon. 

An electron is promoted to create four singly occupied orbitals for bonding for each Carbon.

 [He] 2s2 2p2

6C

C2H4 bonds should all be equal, but remember that s bonds are stronger than p bonds, so nature has to do something to make the orbitals uniform. That something is hybridization.

To create equal bond strength, we mix different orbitals and create one set of uniform hybrid orbitals for each Carbon.