The document presents a seminar topic on hybridization given by Tarkesh D. Diwate, which discusses the concepts of sp, sp2, and sp3 hybridization including the properties of hybrid orbitals, shapes of atomic orbitals, types of hybridization, and examples such as ethylene and acetylene. Key aspects covered include how hybrid orbitals are formed by mixing atomic orbitals of similar energies, their orientations and equal energies, and how hybridization explains molecular geometry and bonding properties.

1. GONDWANA UNIVERCITY GADCHIROLI
BRAMHAPURI – 441206 DIST CHANDRAPUR
DEPARTMENT OF CHEMISTRY
SEMINAR TOPIC
HYBRIDIZATION
PRESENTED BY : TARKESH D. DIWATE
M.Sc. 1st YEAR (CHEMISTRY) 2nd SEMISTER
HEAD OF THE DEPARTMENT : Asst. Prof. Y.P. THAWARI SIR

2. CONTENT
 Introduction
 Properties of hybrid orbital
 Shape of atomic orbital (s , p , d-orbital )
 Important points
 Types of hybridisation
 Sp hybridisation
 Sp2 hybridisation
 Reference

3. Introduction
 Mixing of dissimilar orbital of similar energies to form
new orbital is known as hybridization. And new
orbital formed are called hybrid orbital.
 Hybrid orbital are very useful in the explanation of
molecular geometry and atomic bonding properties.

4. Properties of hybrid orbital
 The no. Of hybrid orbital formed is equal to number
of atomic orbital mixed.
 All hybrid orbital have equal energy .
 The hybrid orbital are oriented in space in fixed
direction. Therefore, molecule formed has fix
geometry.

5. Shape of atomic orbital
 S – orbital : spherical in shape.

6.  Shape of p – orbital : it is dumbbell shape

7.  Shape of d – orbital : it is double dumbbell shape

8. Important points to study the
hybridisation
 Hybridisation is not a real physical process but is a
concept which has been introduced to explain some
structural properties which could not be explained by
simple valence bond theory.
 Only orbital of similar energies are belonging to the
same atom or ion undergo hybridisation.
 Hybrid orbital lead to the formation of bonds known as
hybrid bonds which are stonger than the non hybrid.
 Hybridised orbital are dumb-bell type i.e. one loop larger
and one is smaller.

9. Types of hybridisation

10. Sp hybridisation :
 The hybridisation of one s-orbital and one p-orbital is
called sp hybridisation.

11. • Two hybrid orbital are formed are called sp hybrid orbital. Ψ1
and Ψ2 may be expressed as :
Ψ1 = a1s +b1p ------------(1)
Ψ2 = a2s + b2p -----------(2)
where a1, a2, b1, b2 are linear combination coefficient .
The value of linear combination coefficient a1 , b1 , a2 , b2 may be
consider as ;
1 ) Ψ1 and Ψ2 are normalised
𝑎2 + 𝑏2 = 1 -----------(3)
𝑎2 + 𝑏2 = 1 --------(4)
2) Ψ1 and Ψ2 are orthogonal
a1a2 + b1b2 = 0 -----------(5)
3) Ψ1 and Ψ are equivalent
since the s-atomic orbital is spherically symmetric and the
two hybrid orbital Ψ1 and Ψ2 are equivalent ,the share of s
function is equal in both Ψ1 and Ψ2.
1
1
2 2

12. therefore , 𝑎2
+ 𝑎2
= 1
But , 𝑎2
= 𝑎2
= 𝑎2
=> 2 𝑎2
= 1
𝑎2
= ½
a =
1
2
a1 = a2 = =
1
2
If Ψ1 and Ψ2 are normalised
then eq (3) become ,
𝑎2 + 𝑏2 = 1
½ + b1² = 1
b1² = 1 - ½
b1² = ½
b1 =
1
2
1 2
1 1

13. Ψ1 and Ψ2 are orthogonal , then the eq. (5) become ,
a1a2 + b1b2 = 0
1
2
∗
1
2
+
1
2
(b2) = 0
½ +
1
2
(b2) = 0
b2 =
1
2
therefor , a1 = a2 =
1
2
, b1 =
1
2
, b2 = -
1
2
putting the value of linear combinant coefficient in eq. (1) and eq. (2)
We get ,
from eq (1),
Ψ1 =
1
2
s +
1
2
p
Ψ1 =
1
2
(s + p)
from eq. (2) ,
Ψ2 =
1
2
s +
1
2
p
Ψ2 =
1
2
(s – p)

14. Bond angle for sp hybridisation :
In sp hybridisation % of s orbital = 50 % and % of p orbital = 50 %
therefor ,
cos 𝜃 = -(
𝑠 𝑐ℎ𝑎𝑟𝑎𝑐𝑡𝑒𝑟 𝑜𝑓 ℎ𝑦𝑏𝑟𝑖𝑑 𝑜𝑟𝑏𝑖𝑡𝑎𝑙
1−𝑠 𝑐ℎ𝑎𝑟𝑎𝑐𝑡𝑒𝑟 𝑜𝑓 ℎ𝑦𝑏𝑟𝑖𝑑 𝑜𝑟𝑏𝑖𝑡𝑎𝑙
)
cos 𝜃 = - (
1
2
1−1
2
)
cos 𝜃 = - (
1
2
1
2
)
cos 𝜃 = - 1
𝜃 = cos−1
(−1)
𝜃 = 180 °
therefore , the Bond angle for sp hybridisation is 180° .
Example : Acetylene
H C C H
180° 180°

15. Sp2 hybridisation :
 The hybridisation of one s-orbital and two p-orbital is
called sp2 hybridisation.

16. • Three hybrid orbital are formed are called sp2 hybrid orbital. P orbital are
expressed as Ψ1, Ψ2, and Ψ3.
Ψ1 = a1s + b1px + c1py -------- (1)
Ψ2 = a2s + b2px + c2py -------(2)
Ψ3 = a3s + b3px + c3py --------(3)
the coefficient a1 , a2 , a3 , b1 , b2 , b3 , c1 , c2 and c3 can be determine as ;
1) Ψ1 , Ψ2 and Ψ3 are normalised;
𝑎2+𝑏2 + 𝑐2 = 1 -----------(4)
𝑎2+𝑏2 + 𝑐2 = 1 -----------(5)
𝑎2
+ 𝑏2
+ 𝑐2
= 1 -------------(6)
2) Ψ1 , Ψ2 and Ψ3 are orthogonal ;
if Ψ1 and Ψ2 are orthogonal then ,
a1a2 + b1b2 + c1c2 = 0 --------(7)
if Ψ2 and Ψ3 are orthogonal then ,
a2a3 + b2b3 + c2c3 = 0 -------(8)
1 1 1
2 2 2
3 3 3

17. if Ψ1 and Ψ3 are orthogonal then ,
a1a3 + b1b3 + c1c3 = 0 -------(9)
3) Ψ1 , Ψ2 and Ψ3 are equivalent ;
since the s-orbital is spherically symmetrical and the three orbitals
Ψ1 , Ψ2 and Ψ3 are equivalent the share of s function is equal in both Ψ1 , Ψ2 and
Ψ3 then ;
𝑎2
+ 𝑎2
+ 𝑎2
= 1
a1 = a2 = a3 = a
3a² = 1
a² =
1
3
a =
1
3
therefore : a1 = a2 = a3 =
1
3
1 2 3

18. The other linear combination coefficient are ; Px has maxima along x-axis in such
a wave function there will be no contribution from py , i.e. C1 = 0
when Ψ is normalised then eq. (4) become ,
𝑎2
+𝑏2
+ 𝑐2
= 1 (C1 = 0 )
𝑎2
+𝑏2
= 1
1
3
+ b1² = 1
b1² =
2
3
b1 = 2
3
Since Ψ1 and Ψ2 is orthogonal then eq. (7) become ,
a1a2 + b1b2 + c1c2 = 0
1
3
*
1
3
+ 2
3 (b2) + 0 (c2) = 0
b2 = -
1
3
* 3
2
b2 = -
1
6
1 1 1
1 1

19. Ψ2 is normalised then eq. (5) become ,
𝑎2 + 𝑏2 + 𝑐2 = 1
(1
3
)² + (−1
6
)² +c2² = 1
1
3
+
1
6
+ c2²= 1
c2² = 1 -
1
3
-
1
6
c2² =
1
2
c2 =
1
2
2 2 2

20. REFRENCE
1. Principle of physical chemistry :
B.R.PURI , M.S.PATHANIA , L.R SHARMA.
2. Physical chemistry : Atkins.
3. Wikkipidia .