X-ray diffraction.
XRD sends a beam of X-rays at a material and records how its atoms redirect them, which creates a pattern that can show which crystal structures are present.
Patterns from crystal planes.
Two powders can look identical but contain different crystal structures. To find these differences, an XRD test is used. In an XRD test, the material is usually prepared as a fine powder or a flat solid. Inside the machine, an X-ray source aims at the sample while a detector measures the angles at which the rays are redirected. This detector rotates around the sample to measure the intensity of the scattered rays at various angles.
The repeating atomic planes inside a crystal create peaks in reflected X-rays at specific angles. Scientists compare the peak pattern from the sample with known reference data to identify phases and see how processing changed the material.
The result is a pattern of peaks on a graph, with the intensity on the vertical axis and angle on the horizontal axis, which is usually labeled 2θ. Peaks mean more intense rays detected at a particular angle. This graph is called a diffractogram. XRD works best with crystalline phases; glasses and other disordered materials produce broader, less distinct patterns.
See all lab guides ↗
