A crystal lattice is an orderly three-dimensional arrangement of atoms, ions, or molecules in a crystal. The basic repeating unit in a crystal lattice is called a unit cell. The unit cell is defined by lattice parameters: the lengths of its sides (denoted as \(a\), \(b\), and \(c\)) and the angles between them.
Each point in the lattice represents the position of an atom, ion, or molecule. The regular, repeating pattern of these points creates the overall structure of the crystal. The symmetry and dimensions of the unit cell determine the symmetry and properties of the whole crystal.
- Lattice points: Positions that can be occupied by atoms, ions or molecules.
- Unit cell: The smallest repeating unit that shows the full symmetry of the crystal.
- Lattice parameters: Distances and angles that define the unit cell dimensions.
Understanding the crystal lattice is important because it impacts the physical properties of the material. For example, the distance between atoms and the arrangement of atoms in the lattice affect properties like hardness, conductivity, and melting point. Analyzing X-ray diffraction patterns allows scientists to determine the crystal lattice structure and thus infer these properties.