A crystal structure refers to the orderly and repeating arrangement of atoms, ions, or molecules in a solid material. This arrangement forms a three-dimensional lattice, which defines the shape and properties of the crystal. Different materials can have various crystal structures, such as cubic, hexagonal, or tetragonal, influencing their physical characteristics. The study of crystal structures is essential in fields like materials science, chemistry, and mineralogy. Understanding these structures helps scientists predict how materials will behave under different conditions, such as temperature and pressure, and is crucial for applications in electronics, pharmaceuticals, and nanotechnology.