ClF4- Lewis structure

ClF₄^– has one chlorine atom and four fluorine atoms.

In ClF₄^– Lewis structure, there are four single bonds around the chlorine atom, with four fluorine atoms attached to it. Each fluorine atom has three lone pairs, and the chlorine atom has two lone pairs.

Also, there is a negative (-1) charge on the chlorine atom.

Alternative method: Lewis structure of ClF₄^–

Rough sketch

• First, determine the total number of valence electrons

In the periodic table, both chlorine and fluorine lie in group 17.

Hence, both chlorine and fluorine have seven valence electrons.

Since ClF₄^– has one chlorine atom and four fluorine atoms, so…

Valence electrons of one chlorine atom = 7 × 1 = 7
Valence electrons of four fluorine atoms = 7 × 4 = 28

Now the ClF₄^– has a negative (-1) charge, so we have to add one more electron.

So the total valence electrons = 7 + 28 + 1 = 36

Learn how to find: Chlorine valence electrons and Fluorine valence electrons

• Second, find the total electron pairs

We have a total of 36 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 = 36 ÷ 2 = 18

• Third, determine the central atom

We have to place the least electronegative atom at the center.

Since chlorine is less electronegative than fluorine, assume that the central atom is chlorine.

Therefore, place chlorine in the center and fluorines on either side.

• And finally, draw the rough sketch

Lone pair

Here, we have a total of 18 electron pairs. And four Cl — F bonds are already marked. So we have to only mark the remaining fourteen electron pairs as lone pairs on the sketch.

Also remember that chlorine is a period 3 element, so it can keep more than 8 electrons in its last shell. And fluorine is a period 2 element, so it can not keep more than 8 electrons in its 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 chlorine, there are two lone pairs.

Mark the lone pairs on the sketch as follows:

Formal charge

Use the following formula to calculate the formal charges on atoms:

Formal charge = valence electrons – nonbonding electrons – ½ bonding electrons

For chlorine atom, formal charge = 7 – 4 – ½ (8) = -1

For each fluorine atom, formal charge = 7 – 6 – ½ (2) = 0

Here, the chlorine atom has a charge, so mark it on the sketch as follows:

Final structure

The final structure of ClF₄^– contains a central chlorine atom linked to four fluorine atoms through single covalent bonds. In this configuration, the chlorine atom utilizes an expanded valence shell to accommodate twelve electrons, which consist of four bonding pairs and two lone pairs. Within this layout, each of the four fluorine atoms successfully satisfies the octet rule by retaining three lone pairs alongside its single shared bond. This arrangement represents the most stable state for the ion because the negative formal charge is localized on the central chlorine atom, while each fluorine atom maintains a formal charge of zero. Consequently, this specific electronic distribution serves as the definitive and most accurate Lewis representation of ClF₄^–.

To properly represent this as a polyatomic ion, the entire Lewis structure is enclosed within square brackets. The overall charge of 1- is then written as a superscript outside the brackets at the top right, indicating that the structure possesses one additional electron beyond the valence count of the neutral atoms.

Next: ClCN Lewis structure

External video

• How to Draw the Lewis Structure for ClF4 – – YouTube • Wayne Breslyn