SeF5- Lewis structure

SeF₅^– has one selenium atom and five fluorine atoms.

In SeF₅^– Lewis structure, there are five single bonds around the selenium atom, with five fluorine atoms attached to it. Each fluorine atom has three lone pairs, and the selenium atom has one lone pair.

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

Alternative method: Lewis structure of SeF₅^–

Rough sketch

• First, determine the total number of valence electrons

In the periodic table, selenium lies in group 16, and fluorine lies in group 17.

Hence, selenium has six valence electrons and fluorine has seven valence electrons.

Since SeF₅^– has one selenium atom and five fluorine atoms, so…

Valence electrons of one selenium atom = 6 × 1 = 6
Valence electrons of five fluorine atoms = 7 × 5 = 35

Now the SeF₅^– has a negative (-1) charge, so we have to add one more electron.

So the total valence electrons = 6 + 35 + 1 = 42

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

• Second, find the total electron pairs

We have a total of 42 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 = 42 ÷ 2 = 21

• Third, determine the central atom

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

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

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

• And finally, draw the rough sketch

Lone pair

Here, we have a total of 21 electron pairs. And five Se — F bonds are already marked. So we have to only mark the remaining sixteen electron pairs as lone pairs on the sketch.

Also remember that selenium is a period 4 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 selenium, there is one lone pair.

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 selenium atom, formal charge = 6 – 2 – ½ (10) = -1

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

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

Final structure

The final structure of SeF₅^– contains a central selenium atom linked to five fluorine atoms through single covalent bonds. In this arrangement, the selenium atom utilizes an expanded octet to accommodate twelve valence electrons, consisting of five bonding pairs and one lone pair. Each fluorine atom fulfills the octet rule by maintaining three lone pairs of its own. This specific configuration is the most stable because it results in a formal charge of -1 on the central selenium atom and zero on each of the fluorine atoms, representing the most energetically favorable distribution for the ion. Consequently, this electronic pattern serves as the definitive and most accurate Lewis representation for this anion.

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: C₂H₃F Lewis structure

External links

• https://www.chegg.com/homework-help/questions-and-answers/draw-lewis-structure-sef5-ion-sure-explicitly-draw-lone-pairs-electrons-atoms-label-nonzer-q56179859
• https://study.com/academy/answer/what-is-the-lewis-structure-of-sef5.html
• https://oneclass.com/homework-help/chemistry/7026995-sef5-lewis-structure.en.html
• https://brainly.com/question/29592075