CO2 Lewis Structure — Carbon Dioxide Geometry

Before drawing, we must know how many outer-shell (valence) electrons we have to work with.

• Carbon (C): Atomic number 6. Configuration is 2, 4. It has 4 valence electrons.
• Oxygen (O): Atomic number 8. Configuration is 2, 6. Each oxygen has 6 valence electrons. Since there are two oxygen atoms, 6 × 2 = 12.
• Total Valence Electrons = 4 + 12 = 16 electrons.

The least electronegative atom is placed in the center. Carbon is less electronegative than Oxygen, so Carbon sits in the middle: O — C — O

Carbon needs 4 more electrons to complete its octet (8), and each Oxygen needs 2 more.

To make everyone happy with 8 electrons, Carbon forms a Double Covalent Bond with each Oxygen atom.

• A double bond involves sharing 2 pairs of electrons (4 electrons total).

Structure so far: O = C = O

We have 16 total electrons. We used 8 electrons in the two double bonds (4 per double bond). Remaining electrons = 16 - 8 = 8 electrons.

We place these 8 electrons as non-bonding pairs (Lone Pairs) on the Oxygen atoms to complete their octets.

• Left Oxygen gets 4 dots (2 lone pairs).
• Right Oxygen gets 4 dots (2 lone pairs).
• Carbon in the center already has 8 electrons from the double bonds, so it gets no lone pairs.

Because there are no lone pairs pushing down from the central carbon atom, the two double bonds push as far away from each other as possible (180°).

This makes the CO₂ molecule perfectly Linear in shape. Furthermore, because the two highly electronegative oxygen atoms are pulling equally in exact opposite directions, the individual dipole moments cancel out, making CO₂ a Non-Polar molecule.