What is the Difference Between X-ray Diffraction and X-ray Fluorescence

The key difference between X-ray diffraction and X-ray fluorescence is that X-ray diffraction can be used to determine the presence and amounts of mineral species in a sample and to identify phases, whereas X-ray fluorescence can be used to determine the elemental composition of materials, but not the phases.

When considering the applications of X-ray diffraction and X-ray fluorescent methods, they are useful in elemental analysis, mining and geology, cement manufacturing, sample identification, quality control, regulatory compliance, and environmental analysis.

CONTENTS

1. Overview and Key Difference
2. What is X-ray Diffraction 
3. What is X-ray Fluorescence 
4. X-ray Diffraction vs X-ray Fluorescence in Tabular Form
5. Summary – X-ray Diffraction vs X-ray Fluorescence

What is X-ray Diffraction?

X-ray diffraction or X-ray crystallography is an analytical technique that we use to determine the structure of crystals. Hence, the theory behind the technique involves the diffraction of an incident X-ray beam in different directions. In brief, by measuring the angles and intensities of the diffracted beams, we can determine the 3D picture of the electron density within that crystal. Consequently, the electron densities give the positions of atoms in the crystal structure. We can determine the chemical bonds and various other information as well.

Crystals have regularly arranged atoms. X-rays are waves of electromagnetic radiation. Therefore, the atoms in the crystal can scatter the X-ray beams through the electrons of the atoms. As a result, X rays striking the electrons produce secondary waves (spherical waves) emerging from the electron. We call this process “elastic scattering,” and the electron acts as the scatterer. However, these waves cancel one another via destructive interference.

What is X-ray Fluorescence?

X-ray fluorescence can be described as the emission of characteristic secondary X-rays from materials that have been excited after being bombarded with high-energy X-rays or gamma rays. It is denoted by XRD. This phenomenon is highly useful in elemental analysis and chemical analysis, particularly for the investigation of metals, glass, ceramics, and building materials. It is also useful for geochemistry, forensic science, archeology, and art objects, including paintings.

A primary X-ray beam can be used to excite fluorescent radiation from a sample. This discovery was made in 1928 by Glocker and Schreiber. At present, X-ray fluorescence is useful as a non-destructive analytical technique that can be described as a process-controlled tool in many extractive and processing industries.

What is the Difference Between X-ray Diffraction and X-ray Fluorescence?

X-ray diffraction or X-ray crystallography is an analytical technique that we use to determine the structure of crystals, while X-ray fluorescence is the emission of characteristic secondary X-rays from materials that have been excited after being bombarded with high-energy X-rays or gamma rays. The key difference between X-ray diffraction and X-ray fluorescence is that X-ray diffraction can be used to determine the presence and amounts of mineral species in a sample and to identify phases, whereas X-ray fluorescence can be used to determine the elemental composition of materials, but not the phases.

The following table summarizes the difference between X-ray diffraction and X-ray fluorescence.

Summary – X-ray Diffraction vs X-ray Fluorescence

The key difference between X-ray diffraction and X-ray fluorescence is that X-ray diffraction can be used to determine the presence and amounts of mineral species in a sample and to identify phases, whereas X-ray fluorescence can be used to determine the elemental composition of materials, but not the phases of materials. Both these methods have applications in elemental analysis, mining and geology, sample identification, quality control, cement manufacturing, regulatory compliance, and environmental analysis.

Reference:

1. “X-Ray Fluorescence (XRF).” Techniques, 21 Jan. 2020.

Image Courtesy:

1. “LDAutoXRFPic” By LinguisticDemographer at English Wikipedia – Transferred from en.Wikipedia to Commons by Cdang using CommonsHelper. (Public Domain) via Commons Wikimedia
2. “X-ray fluorescence simple figure” By Calvero. – Selfmade with ChemDraw. (Public Domain) via Commons Wikimedia