Lewis Structure of SeF5- (With 5 Simple Steps to Draw!) (2024)

Lewis structure of SeF5- ion contains five single bonds between the Selenium (Se) atom and each Fluorine (F) atom. The Selenium atom (Se) is at the center and it is surrounded by 5 Fluorine atoms (F). The Selenium atom has 1 lone pair while all the five Fluorine atoms have 3 lone pairs. The Selenium atom has -1 formal charge.

Let’s draw and understand this lewis dot structure step by step.

(Note: Take a pen and paper with you and try to draw this lewis structure along with me. I am sure you will definitely learn how to draw lewis structure of SeF5- ion).

5 Steps to Draw the Lewis Structure of SeF5- ion

Step #1: Calculate the total number of valence electrons

Here, the given ion is SeF5- ion. In order to draw the lewis structure of SeF5-, first of all you have to find the total number of valence electrons present in the SeF5- ion.
(Valence electrons are the number of electrons present in the outermost shell of an atom).

So, let’s calculate this first.

Calculation of valence electrons in SeF5- ion

• For Selenium:

Selenium is a group 16 element on the periodic table. ^[1]

Hence, the valence electrons present in selenium is 6 (see below image).

• For Fluorine:

Fluorine is a group 17 element on the periodic table. ^[2]

Hence, the valence electrons present in fluorine is 7 (see below image).

Hence in a SeF5- ion,

Valence electrons given by Selenium (Se) atom = 6
Valence electrons given by each Fluorine (F) atom = 7
Electron due to -1 charge, 1 more electron is added
So, total number of Valence electrons in SeF5- ion = 6 + 7(5) + 1 = 42

Step #2: Select the center atom

While selecting the atom, always put the least electronegative atom at the center.

(Remember: Fluorine is the most electronegative element on the periodic table and the electronegativity decreases as we move right to left in the periodic table as well as top to bottom in the periodic table). [3]

Here in the SeF5 molecule, if we compare the Selenium atom (Se) and Fluorine atom (F), then Selenium is less electronegative than fluorine.

So, selenium should be placed in the center and the remaining 5 fluorine atoms will surround it.

Step #3: Put two electrons between the atoms to represent a chemical bond

Now in the above sketch of SeF5 molecule, put the two electrons (i.e electron pair) between each Selenium atom and fluorine atom to represent a chemical bond between them.

These pairs of electrons present between the Selenium (Se) and Fluorine (F) atoms form a chemical bond, which bonds the selenium and fluorine atoms with each other in a SeF5 molecule.

Step #4: Complete the octet (or duplet) on outside atoms. If the valence electrons are left, then put the valence electrons pair on the central atom

Don’t worry, I’ll explain!

In the Lewis structure of SeF5, the outer atoms are fluorine atoms.

So now, you have to complete the octet on these fluorine atoms (because fluorine requires 8 electrons to have a complete outer shell).

Now, you can see in the above image that all the fluorine atoms form an octet.

Also, only 40 valence electrons of SeF5- ion are used in the above structure.

But there are total 42 valence electrons in SeF5- ion (as calculated in step #1).

So the number of electrons left to be kept on the central atom = 42 – 40 = 2.

So let’s keep these two electrons (i.e 1 electron pair) on the central atom.

Now, let’s move to the next step.

Step #5: Final step – Check the stability of lewis structure by calculating the formal charge on each atom

Now, you have come to the final step and here you have to check the formal charge on selenium atom (Se) as well as each fluorine atom (F).

For that, you need to remember the formula of formal charge;

Formal charge = Valence electrons – Nonbonding electrons – (Bonding electrons)/2

• For Selenium:
  Valence electrons = 6 (as it is in group 16)
  Nonbonding electrons = 2
  Bonding electrons = 10
• For Fluorine:
  Valence electron = 7 (as it is in group 17)
  Nonbonding electrons = 6
  Bonding electrons = 2

Let’s keep these charges on the atoms in the above lewis structure.

As you can see in the above sketch, there is one -ve charge on the selenium atom, which indicates the -1 formal charge on the SeF5 molecule.

Hence, the above lewis structure of SeF5- ion is the stable lewis structure.

Each electron pair (:) in the lewis dot structure of SeF5- ion represents the single bond ( | ). So the above lewis dot structure of SeF5- ion can also be represented as shown below.

Related lewis structures for your practice:
Lewis Structure of C2H3F
Lewis Structure of NH2F
Lewis Structure of SeI2
Lewis Structure of H2Te
Lewis Structure of TeCl2

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