SiF5- Lewis structure

SiF₅^– has one silicon atom and five fluorine atoms.

In SiF₅^– Lewis structure, there are five single bonds around the silicon atom, with five fluorine atoms attached to it, and on each fluorine atom, there are three lone pairs.

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

Alternative method: Lewis structure of SiF₅^–

Rough sketch

• First, determine the total number of valence electrons

In the periodic table, silicon lies in group 14, and fluorine lies in group 17.

Hence, silicon has four valence electrons and fluorine has seven valence electrons.

Since SiF₅^– has one silicon atom and five fluorine atoms, so…

Valence electrons of one silicon atom = 4 × 1 = 4
Valence electrons of five fluorine atoms = 7 × 5 = 35

Now the SiF₅^– has a negative (-1) charge, so we have to add one more electron.

So the total valence electrons = 4 + 35 + 1 = 40

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

• Second, find the total electron pairs

We have a total of 40 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 = 40 ÷ 2 = 20

• Third, determine the central atom

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

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

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

• And finally, draw the rough sketch

Lone pair

Here, we have a total of 20 electron pairs. And five Si — F bonds are already marked. So we have to only mark the remaining fifteen electron pairs as lone pairs on the sketch.

Also remember that silicon 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 silicon, there is zero lone pair because all fifteen 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 silicon atom, formal charge = 4 – 0 – ½ (10) = -1

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

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

Final structure

The final structure of SiF₅^– features a central silicon atom connected to five fluorine atoms through single covalent bonds. In this configuration, the silicon atom utilizes an expanded valence shell to accommodate ten electrons, forming five shared pairs. Within this layout, each of the five fluorine atoms satisfies the octet rule by maintaining three lone pairs alongside its single shared bond. This arrangement represents the most stable state for the ion because it results in a formal charge of -1 on the central silicon atom, while all five fluorine atoms carry a formal charge of zero. Accordingly, this specific electronic distribution serves as the definitive and most accurate Lewis representation of the SiF₅^– 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.

Next: SeBr₂ Lewis structure

External links

• https://www.chegg.com/homework-help/questions-and-answers/draw-lewis-structure-sif5-answer-following-questions-based-drawing-1-central-silicon-atom–q6500317
• https://www.bartleby.com/questions-and-answers/draw-a-lewis-structure-forsif5-and-answer-the-following-questions-based-on-your-drawing./833beeae-e688-4969-af0a-9ba8e32e9ae0
• https://brainly.com/question/29607759
• https://www.numerade.com/ask/question/draw-a-lewis-structure-for-sif5-do-not-include-overall-ion-charges-or-formal-charges-in-your-drawing-if-the-species-contains-oxygen-do-not-draw-double-bonds-to-oxygen-unless-they-are-needed-50265/