X-ray diffraction is a non-destructive technique used to analyze the structure of crystalline materials. Bragg's law explains how x-rays interfere and diffract when hitting the regular atomic planes of a crystal. In 1914, Knipping and Von Laue discovered that crystals act as three-dimensional diffraction gratings for x-ray wavelengths similar to the spacing of planes in the atomic lattice. Bragg later provided a simple and precise explanation for the diffraction patterns seen in crystal structures. Today, x-ray diffraction is used to determine crystal structures, grain size, strain, and other structural properties of materials.

1. X-RAY DIFFRACTION
By-
Manish Sahu
M.Sc. Chemistry (Final)
Sp.- Physical Chemistry

2. CONTENTS
• Introduction
• History
• Bragg’s law
• X-Ray Diffraction
• Basis of crystallography
• Seven crystal system
• Method of X-Ray diffraction
• Basis features of typical x-ray
• Application
• Uses
• Error
• Conclusion
• References

3. Introduction:-
• It is a non-destructive analytical techniques used to
study the structure, composition and physical properties
of materials.
• Bragg’s law is used to explain the interference pattern of
X-rays.
• It is commonly known as X-ray diffraction or X-ray wave
interference.

4. History:-
• In 1895 discovery of X-ray production by Willem
Roentgen.
• In 1914 discovery of X-ray diffraction pattern by
knipping and Von Laue.
• In 1915 theory of X-ray diffraction pattern by
Bragg.

5. Bragg’s law
λ = 2dsinθ

6. ……………
 Crystalline material consist of parallel rows of atoms
separated by unique distances.
 Diffraction occurs when a beam enter a crystalline
substance and is scattered.
 Direction and intensity of diffraction depends on
orientation of the crystal lattice with radiation.

7. DERIVATION
Since we know that
λ = AB + BC --------(1)
But, AB = BC
λ = 2AB --------(2)
But, AB = dsinθ --------(3)
From equation (2) we get,
λ = 2 ( dsinθ )
λ = 2dsinθ (by equation (3))
λ = 2dsinθ
This equation is known as Bragg’s equation.

8. X-RAY DIFFRACTION:-
 Non distractive analytical technique for identification
and quantitative determination of various crystalline
from known as phases.
 Identification is achieved by comparing the X-ray
diffraction pattern.
 The atomic planes of a crystal cause an incident beam
of X-ray to interference with one another as they leave
the crystal. This phenomenon is called X-ray
diffraction.

9. Fig:- X-ray diffraction

10. BASIC OF CRYSTALLOGRAPHY:-
 A crystal consist of periodic arrangement of the unit
cell into a lattice.
 A unit cell can contain a single atom or atom in a fixed
rearrangement.
 A crystal lattice is a regular 3D distribution of atom in
space.

11. SEVEN CRYSTAL SYSTEM:-

13. (1) Laue’s photographic method:-
Fig:- Laue’s method Fig:- Laue pattern

15. (2) Powder method:-
Fig:- powder crystal method.

16. APPLICATION:-
 It is a non distractive technique.
 To determine crystalline phases and orientation.
 To determine the structural properties such as
Grain
Size
Strain
Shape
Lattice parameters.
 To determine atomic arrangement.

17. USES:-
 Obtain X-ray diffraction pattern.
 Measure d-spacing.
 Obtain integrated intensities.

18. ERRORS:-
 Speciment displacement.
 Errors in zero position.
 Instrument misalingnment.

19. CONCLUSION:-
 Non- destructive, fast, easy sample preparation.
 High-accuracy for d-spacing calculation.
 Standard are available for thousand of material
systems.

20. References:-
 Chatwal G.R., Instrumental method of chemical analysis,
1st edition, Himalaya Publishing house; 2004, page No.
2.303 – 2.332
 Sharma B.K., Instrumental method of chemical analysis,
24th edition, Goel Publishing house; 2006, page No. 329-
359
 Gurtu-Gurtu , Biophysical chemistry , 5th edition, 2010
page No. 195-202