Magnetic properties of transition metal complexes

1. National Institute Of
Technology,Durgapur
Subject : Magnetic Properties of Transition Metal
Complexes
M.Sc. ( 1st Semester )
Name : Payel Maity
Roll Number : 18CY4501
Year :2019

2. Index :
• Magnetism
• Classification
• Theoritical Magnetic Moment Calculation
• Orbital angular moment
• Some Magnetic properties
• Curie Law
• Gauy’s Method to measure Magnetic
Susceptibility

3. : MAGNETISM :
• A charged body in motion always creates a magnetic field
around itself.
• An electron has two types of motion-----
i) spin motion
ii) orbital motion
• Orbital motion of electron generates current and magnetic field.
• Spin motion of electron about its own axis also generates a
magnetic field.

4. : Classification :
Magnetism
Paramagnetism
(when placed in a magnetic field suffer
attraction by the field)
Magnetically concentrated
Ferromagnetism
(magnetic properties increases)
Ferrimagnetism
(magnetic properties decreases)
Diamagnetism
(when placed in a magnetic field suffer
repulsion by the field)
Magneticallly dilute
Antiferromagnetism
(magnetic properties decreases)

6. Theoritical magnetic moment
calculation :
• Spin motion creates spin magnetic moment (µ ֧ / µ-spin only)
Orbital motion creates orbital magnetic moment (µʵ)
• here,
g ֧= Gyromagnetic ratio or, Lande splitting factor for spin moment
S = Resultant spin value ( S= S₁+S₂+S₃+......)
For most of the cases,
g ֧= 2.0
S = n/2 ,where n= number of unpaired electron

7. Orbital angular moment (µɩ )
L = resultant azimuthal quantum number,
g = Lande splitting factor for orbital moment
For most of the cases,
g = 1.0
Overall magnetic moment = vectorial sum of
=
Number of unpaired electron(s) Spin magnetic moment (µ ֧ )
1 1.73
2 2.84
3 3.90
4 4.89
5 5.91

8. 1 Cm
1 dyne
• Pole Strength : If two unit poles of a magnet are 1cm apart from each other they feel
a force of attraction or repulsion of 1dyne -----This is called the pole strength.
• The intensity of magnetic field is proportional to the lines of force.
( I α lines of force )
• Intensity of Magnetisation : It is represented by I. And
I = (pole strength / area)
= (m / A)
= (mL / AL)
= (magnetic moment / volume )
Magnetic Induction : from Gauss’s law
B = H + 4ΠI { where,B= magnetic induction,
H = applied magnetic field
I= intensity of magnetisation }
Magnetic Permeability : P = (B / H)
= Intensity of magnetic line of force within the body.

9. Magnetic Susceptibility : P = (B/H )
= (H + 4ΠI )
=1 +4Π(I /H)
(I/H) is called Magnetic Susceptibility and denoted by χ (kappa / ki)
Gram Susceptibility :
{ ρ =density of the substance}
Molar susceotibility :
{ M=molecular weight }
Curie Law : All paramagnetic substances obey Curie law.
{c is the Curie constant }

10. Plot of Molar Magnetic Susceptibility Vs.
Temperature :

11. Gouy’s Method to measure the
Magnetic susceptibilities
• We can measure properties of a sample by hanging a vial of
material from a balance so that it sits partly in a magnetic
field.
• --- The sample will be pulled down into the magnet if it
contains unpaired electrons (said to be paramagnetic )
• --- It will tend to be pushed out of the field if it contains no
unpaired electrons (diamagnetic).
• The amount of material in the vial along with the extent to
which the sample is pulled into the magnet allows us to
calculate the magnetic susceptibility of the sample.
• --- Sample with a high magnetic susceptibility is strongly
pulled into the magnetic field.

12. Pictorial Representation :

13. Thank you