X-Ray Diffraction (XRD) is a crystallographic method for analyzing the atomic and molecular structure of crystals. XRD works by firing X-rays at a crystalline sample and measuring the angles and intensities of diffracted rays. This diffraction pattern can be used to determine the sample's crystal structure, including its unit cell dimensions and atomic positions. XRD techniques include Bragg's Law, which describes diffraction from crystal planes, and X-ray diffractometers, which contain an X-ray source, sample holder, and detector. XRD has many applications including determining crystal structures, identifying materials, and analyzing particle size and crystallinity.

1. X-Ray Diffraction
(XRD)
By: Shumookh Turki AlSufyani
LinkedIn: Shumookh AlSufyani

2. ➢ Introduction
➢ X-Ray Diffraction
➢ Basics of Crystallography
➢ Crystals & Diffraction of X-ray
➢ XRD Techniques
➢ X-Ray Diffractometer
➢ Application Of X-Ray Diffraction
Contents:

3. Introduction:
c
Introduction
X-Ray
It’s a wave discovered in 1895 By
Wilhelm Conrad Roentgen
• Wavelength:
10 picometers to 10 nanometers
• frequencies :
30 petahertz to 30 exahertz
• Energies:
145 eV to 124 keV.

4. X-Ray Interactions:
c
Introduction
Scattering Absorbance

5. c
X-Ray Diffraction (XRD)
X-Ray Diffraction (XRD):
❑ It’s a method of X-ray crystallography (method of determining the arrangement of atoms
within a crystal), in which a beam of X-rays strikes a sample (crystalline solid), land on a piece
of film or other detector to produce scattered beams.
❑ These beams make a diffraction pattern of spots,
the strength and angles of these beams are recorded
as sample is gradually rotated

6. c
Basics of Crystallography
Basics of Crystallography:
Solid Structure
Amorphas Crystalline

7. c
Basics of Crystallography
Basics of Crystallography:
❑ The unit cell is the smallest 3D which can be to describe the 3D lattice of a solid. The
edges (a, b, and c) and inter-edge angles (a, ẞ, and y) of the unit cell are known as
the lattice parameters of a crystalline solid.

8. ❑ Interplanar distance (d-Spacing) for
Cubic crystal: 𝒅𝒉𝒌𝑰 =
𝒂𝟐
𝒉𝟐×𝒌𝟐×𝑰𝟐
c
Basics of Crystallography
Basics of Crystallography:
❑ The plan of structure crystal is (x,y,z)
Also Known as the Miller indices (h,k,l)
(Lift Right ,Front Back ,Up Down)

9. c
Crystals & Diffraction of X-ray
Crystals & Diffraction of X-ray:
1. The Laue equations:
Diffraction from a hypothetical ID crystal, constituting a row
of atoms, may be treated in the same way as diffraction of light
by an optical grating, A real crystal is a 3D arrangement of
atoms for which three Laue equations may be written as follows:
𝒂𝟏𝐬𝐢𝐧 ∅𝟏 = 𝒏𝝀 𝒂𝟐 𝒔𝒊𝒏 ∅𝟐 = 𝒏𝝀 𝒂𝟑 𝒔𝒊𝒏 ∅𝟑 = 𝒏𝝀
• It’s provided a rigorous and mathematically correct way to
describe diffraction by crystals.
• The drawback is that they are cumbersome to use.

10. c
Crystals & Diffraction of X-ray
Crystals & Diffraction of X-ray:
2. Bragg’s Law :
The Bragg approach to diffraction is to regard crystals as built up in layers or planes
such that each acts as a semi-transparent mirror. Some of the X-rays are reflected off a
plane with an angle of reflection equal to the angle of incidence. ( 𝒏𝝀 = 𝟐𝒅𝒉𝒌𝑰 sin 𝜽 )

11. c
XRD Techniques
XRD Techniques
Variable 𝝀
Solid piece
Film Detector
Laue
Fixed 𝝀
Single crystal sample
Film Detector
Precession
(Buerger)
Weissenbberg
Rotation (Oscillation)
Counter Detector
Automatic
Diffractometer
Powder sample
Film Detector
Guinier
(Focusing)
Debya-Scherrer
Counter Detector
Diffractometer

12. c
X-Ray Diffractometer :
X-Ray Diffractometer
❑ It’s an instrument for studying crystalline materials by measurement of the way in which they
diffract (Scatter) x-ray of known wavelength.
Component of an
X-Ray
Diffractometer
X-ray Source
Specimen (sample)
X-ray Detector

13. c
X-Ray Diffractometer
XRD Of Geometries:
Reflection
Transmission
• Bragg-Brentano geometry
• Best for strongly absorbing sample
• Requires flat sample surface
• Easy adapted for in situ investigations
• Debye-Scherrer geometry
• Best for samples with low absorption
• Capillaries can be used as sample holders
(measurement of air sensitive sample suspension)

14. c
X-Ray Diffractometer :
1- X-ray Source :
Accelerate electrons in a particle accelerator
Fire beam of electrons at metal target
Electrons accelerated at relativistic velocities circular
orbits.
Ionization of inner shell electrons results in formation
of an “electron hole”
As velocities approach the speed of light, they emit
electromagnetic radiation in the x-ray region
Relaxation of electrons from upper shells, the energy
difference is released in the form of x-rays of specific
wavelengths
The x-rays produced have arrange of wavelengths
(white radiation or Bremsstrahung)
Commonly used metals are Co, Mo
Results in high flux of –rays.
Very inefficient, most energy dissipated at heat
(requires permanent cooling)
The Source is Synchroton
The Source is X-ray tube

15. 3- X-ray Detector:
c
X-Ray Diffractometer
There are three main types of detector used in X-ray diffractometers;
❑ proportional detector : is probably used For instrument dedicated for powder works,
❑ Scintillation detector: although still available is not widely used in new types of
diffractometer..
❑ Semiconductor detector: offers many advantages. (e.g very efficient).

16. c
■ Determining the
complex structures of
metals and alloys
■ Characterization of
crystalline materials
■Structure of Crystals
■ Identification of fine-
grained minerals such as
clays and mixed layer
clays.
■ Determination of unit
cell dimensions
■ Particle size analysis
■ Polymer
Characterization
■ Identification Of purity
■ Degree of crystallinity
Application Of XRD :
Application Of XRD

17. • https://en.wikipedia.org/wiki/X-ray
• Solid State Chemistry and it’s Applications, Anthony R. West. (2014), (2nd Edition- Student Edition).UK.
Department of Materials Science and Engineering
• Advances in neutron radiography and tomography, M Strobl, I Manke, N Kardjilov, A Hilger, M Dawson and
J Banhart. (2009), J. Phys. D: Appl. Phys. doi:10.1088/0022-3727/42/24/243001
References: