67. Covalent Bonding(13)- sp3d3 , sp3d4 Hybridization.

sp3d3 hybridization

The process of mixing 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 that 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 a 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 an oxidation state of 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 pure atomic orbitals.

• The hybrid orbitals are always 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 the study of 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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