X-ray powder diffraction is a widely used analytical technique in materials science, chemistry, and physics. It's used to determine the atomic and molecular structure of a crystalline material by analyzing the diffraction pattern of X-rays that are scattered by the material. This technique is based on the principle that the X-rays that are scattered by the atoms in the material will interfere constructively or destructively, depending on their relative positions. By analyzing the diffraction pattern, researchers can determine the positions of the atoms in the crystal lattice and the distances between them, which can provide important information about the material's properties and behavior.