In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal.
A crystal structure is composed of a unit cell, a set of atoms arranged in a particular way; which is periodically repeated in three dimensions on a lattice.
The spacings between unit cells in various directions are called its lattice parameters. The symmetry properties of the crystal are embodied in its space group. A crystal's structure and symmetry play a role in determining many of its properties, such as cleavage, electronic band structure, and optical properties.
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