SbF6- Lewis structure

SbF₆^– has one antimony atom and six fluorine atoms.

In SbF₆^– Lewis structure, there are six single bonds around the antimony atom, with six fluorine atoms attached to it, and on each fluorine atom, there are three lone pairs.

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

Alternative method: Lewis structure of SbF₆^–

Rough sketch

• First, determine the total number of valence electrons

In the periodic table, antimony lies in group 15, and fluorine lies in group 17.

Hence, antimony has five valence electrons and fluorine has seven valence electrons.

Since SbF₆^– has one antimony atom and six fluorine atoms, so…

Valence electrons of one antimony atom = 5 × 1 = 5
Valence electrons of six fluorine atoms = 7 × 6 = 42

Now the SbF₆^– has a negative (-1) charge, so we have to add one more electron.

So the total valence electrons = 5 + 42 + 1 = 48

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

• Second, find the total electron pairs

We have a total of 48 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 = 48 ÷ 2 = 24

• Third, determine the central atom

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

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

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

• And finally, draw the rough sketch

Lone pair

Here, we have a total of 24 electron pairs. And six Sb — F bonds are already marked. So we have to only mark the remaining eighteen electron pairs as lone pairs on the sketch.

Also remember that antimony is a period 5 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 antimony, there is zero lone pair because all eighteen electron pairs are over.

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 antimony atom, formal charge = 5 – 0 – ½ (12) = -1

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

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

Final structure

The final structure of SbF₆^– features a central antimony atom connected to six fluorine atoms through single covalent bonds. In this arrangement, the antimony atom serves as an exception to the octet rule, utilizing an expanded valence shell to accommodate twelve electrons across six bonding pairs. Each fluorine atom fulfills its octet by maintaining three lone pairs of its own alongside the single shared bond. This configuration is the most stable because it optimizes the formal charge distribution; the central antimony atom carries a formal charge of -1, while all six fluorine atoms maintain a formal charge of zero. Consequently, this specific electronic distribution serves as the definitive and most accurate Lewis representation of the SbF₆^– ion.

To complete the representation, draw square brackets around the entire Lewis structure and place a “-” or “-1” sign as a superscript outside the upper right bracket. This notation signifies that the negative charge is a property of the whole ion, resulting from the additional electron included in the total valence electron count to reach this stable configuration.

Next: SbCl₃ Lewis structure

External links

• https://www.numerade.com/ask/question/draw-lewis-structures-for-sbf6-teo2f2-tef5-xef4-xef82-cso-i3-b3n3h6cyclic-the-first-atom-listed-is-the-central-atom-for-all-except-b3n3h6-show-all-lone-pairs-and-indicate-any-non-zero-formal-10558/
• https://www.chegg.com/homework-help/questions-and-answers/sbf6-best-lewis-structure-q15815733