67.CHEMICAL BONDING (14)- Covalent Bonding(13)- sp3d3 Hybridization(8).

Sp3d3 hybridization

The process of mixing of one s- orbital ,three p- orbitals and three d-orbitals in an atom to form seven sp3  d3 hybrid orbitals of equivalent energy is called sp3 d3 hybridization.

EXAMPLE  1 – IODINE HEPTAFLUORIDE (IF7)

Iodine is a p-block element and it has 7 valence electrons.Both iodine and fluorine are halogens and thus iodine heptafluoride is an interhalogen compound – a compound formed between two halogens.In this compound, iodine is the central atom which undergoes hybridization.

Iodine (53)  1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p5  → Ground state

One s and two 5p electrons get excited to the vacant d-orbital, which gives rise to 7 unpaired electrons. The 5s,5p and 5d orbitals hybridise to form seven sp3  d3 hybrid orbitals.The molecule is then formed with 7 fluorine atoms.

671

The geometry of this molecule is pentagonal bipyramidal . Five F atoms are in one plane directed at corners of a pentagon (equatorial position), with 72º angle between them. One F atom is above and one F atom below the plane of the pentagon(Axial positions). The angle between axial and equatorial F atoms is 90º.

672

 

 

The 3D structure can be represented as follows –

673

 

Sp3d4 hybridization

This type of hybridization is very rare as it demands the central atom to be bonded to eight different atoms/ligands. Very few elements show oxidation state more than +7 (e.g.– Mn+7) . We shall not study this in detail as its occurrence is very rare. 

 

The key points to remember about the hybridization theory are –

• # of atomic orbitals mixed = # of atomic orbitals obtained.

• The electrons in unhybridized p orbitals form π bonds.

•  Hybrid orbitals form more stable bonds than the pure atomic orbitals.

• The hybrid orbitals are aways equivalent in energy and shape.

• The type of hybridization depends on how many atomic orbitals are mixed (this depends on the reaction conditions) .

No.of substituents on the central atom

No. of hybrid orbitals

Hybrid orbitals

Type of hybridisation

Ideal Geometry

Bond Angle/s

7

7

one s + three p + three d

sp3d3

Pentagonal bipyramidal

72º , 90º

6

6

one s + three p + two d

sp3d2

Octahedral

90º

5

5

one s + three p + one d

sp3d

Triagonal bipyramidal (TBP)

120º , 90º

4

4

   one s + three p

sp3

Tetrahedral

109.5º

3

3

one s + two p

sp2

Triagonal Planar

120º

2

2

one s + one p

sp

Ⅼinear

180º

With this post we complete studying all types of hybridizations. In the next post we will study a new rule, which is important in our study on hybridization theory.Till then,

Be a perpetual student of life and keep learning ….

Good day!!

 

Image source –

  1. https://www.google.co.in/search?q=if7+geometry&source=lnms&tbm=isch&sa=X&ved=0ahUKEwix0Oe9x4XeAhWUUn0KHSUJBN8Q_AUIDigB&biw=1280&bih=649#imgrc=1n-BIkYsHJkM6M:

 

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