X-ray diffraction (XRD) is a scientific technique used to analyze the structure of crystalline materials. By directing X-rays at a sample, the X-rays are scattered in specific directions, creating a pattern that can be measured. This pattern provides information about the arrangement of atoms within the crystal, helping researchers identify the material and its properties. XRD is widely used in various fields, including materials science, chemistry, and geology. It can help in determining the phase composition of a sample, measuring crystallite size, and assessing strain in materials. This makes XRD a valuable tool for studying substances like minerals, metals, and polymers.