CF2 (difluorocarbene) has one carbon atom and two fluorine atoms.
In CF2 Lewis structure, there are two single bonds around the carbon atom, with two fluorine atoms attached to it. Each fluorine atom has three lone pairs, and the carbon atom has one lone pair.
Steps
To properly draw the CF2 Lewis structure, follow these steps:
#1 Draw a rough sketch of the structure
#2 Next, indicate lone pairs on the atoms
#3 Indicate formal charges on the atoms, if necessary
Let’s break down each step in more detail.
#1 Draw a rough sketch of the structure
- First, determine the total number of valence electrons
In the periodic table, carbon lies in group 14, and fluorine lies in group 17.
Hence, carbon has four valence electrons and fluorine has seven valence electrons.
Since CF2 has one carbon atom and two fluorine atoms, so…
Valence electrons of one carbon atom = 4 × 1 = 4
Valence electrons of two fluorine atoms = 7 × 2 = 14
And the total valence electrons = 4 + 14 = 18
Learn how to find: Carbon valence electrons and Fluorine valence electrons
- Second, find the total electron pairs
We have a total of 18 valence electrons. And when we divide this value by two, we get the value of total electron pairs.
Total electron pairs = total valence electrons ÷ 2
So the total electron pairs = 18 ÷ 2 = 9
- Third, determine the central atom
We have to place the least electronegative atom at the center.
Since carbon is less electronegative than fluorine, assume that the central atom is carbon.
Therefore, place carbon in the center and fluorines on either side.
- And finally, draw the rough sketch
#2 Next, indicate lone pairs on the atoms
Here, we have a total of 9 electron pairs. And two C — F bonds are already marked. So we have to only mark the remaining seven electron pairs as lone pairs on the sketch.
Also remember that both (carbon and fluorine) are the period 2 elements, so they can not keep more than 8 electrons in their last shell.
Always start to mark the lone pairs from outside atoms. Here, the outside atoms are fluorines.
So for each fluorine, there are three lone pairs, and for carbon, there is one lone pair.
Mark the lone pairs on the sketch as follows:
#3 Indicate formal charges on the atoms, if necessary
Use the following formula to calculate the formal charges on atoms:
Formal charge = valence electrons – nonbonding electrons – ½ bonding electrons
For carbon atom, formal charge = 4 – 2 – ½ (4) = 0
For each fluorine atom, formal charge = 7 – 6 – ½ (2) = 0
Here, both carbon and fluorine atoms do not have charges, so no need to mark the charges.
In the above structure, you can see that the central atom (carbon) doesn’t form an octet. But in CF2, carbon has an exception that it does not require eight electrons to form an octet. So no need to worry about the octet rule here.
Therefore, this structure is the stable Lewis structure of CF2.
Next: SeO Lewis structure
External links
- https://www.chegg.com/homework-help/questions-and-answers/cf2-difluoroacetylene-lewis-structure-use-fc-cf-chain-arrangement-sketch-3d-shape-bond-ang-q54740766
- https://www.numerade.com/ask/question/which-of-the-four-following-lewis-structures-is-expected-to-be-the-dominant-lewis-structure-for-the-cf2-molecule-26983/
- https://www.coursehero.com/tutors-problems/Chemistry/27699407-Lewis-Structures/
Deep
Learnool.com was founded by Deep Rana, who is a mechanical engineer by profession and a blogger by passion. He has a good conceptual knowledge on different educational topics and he provides the same on this website. He loves to learn something new everyday and believes that the best utilization of free time is developing a new skill.