To draw the Lewis structure of OCl2 (dichlorine monoxide), we start by determining the total number of valence electrons. Oxygen (O) has 6 valence electrons, and each chlorine (Cl) has 7 valence electrons. Therefore, the total number of valence electrons is:
Total Valence Electrons = 6 (O) + 2 x 7 (Cl) = 20 electrons
Next, we place the oxygen atom in the center because it is less electronegative than chlorine. Then, we connect each chlorine atom to the oxygen atom with a single bond. This uses up 4 electrons (2 for each bond), leaving us with:
Remaining Electrons = 20 – 4 = 16 electrons
Next, we distribute the remaining electrons to satisfy the octet rule. Chlorine can have full outer shells with 8 electrons. By placing 6 electrons (3 lone pairs) around each chlorine, they each have a full octet:
Cl: 2 (bonds) + 6 (lone pairs) = 8 electrons
Now, the oxygen atom needs 4 more electrons to complete its octet. We add 2 lone pairs (4 electrons) to the oxygen, making it:
O: 2 (bonds) + 4 (lone pairs) = 8 electrons
The completed Lewis structure shows the oxygen in the center with two single bonds to each chlorine and two lone pairs on the oxygen:
- O with two single bonds to two Cl atoms on either side.
- Each Cl has three lone pairs.
When considering the geometry of OCl2, we see that the two bonding pairs and two lone pairs around the oxygen create a tetrahedral electron geometry. However, the presence of the lone pairs will lead to a bent or angular molecular geometry.
In summary: The Lewis structure consists of oxygen bonded to two chlorine atoms with two lone pairs on oxygen, resulting in a bent molecular shape.