Yksikkösoluun

Yksikkösoluun (into the unit cell) is the illative form of the Finnish term yksikkösolu, used in crystallography to refer to the unit cell. In crystallography, a unit cell is the smallest repeating unit of a crystal lattice that, through translations in three dimensions, recreates the entire crystal. It is defined by three edge lengths a, b, c and three interaxial angles α, β, γ, collectively called the lattice parameters. The geometry of the unit cell places it within one of seven crystal systems: cubic, tetragonal, orthorhombic, hexagonal, trigonal (rhombohedral), monoclinic, and triclinic. A unit cell can be primitive, containing a single lattice point, or non-primitive, containing additional lattice points such as in body-centered or face-centered lattices.

Crystallographers distinguish between primitive and conventional cells; the latter often fits the symmetry of the lattice and may contain more than one lattice point. The unit cell, together with a basis (the arrangement of atoms tied to each lattice point), defines the crystal structure. The number of formula units per unit cell, Z, depends on the motif and lattice type. The cell volume V is derived from a, b, c and α, β, γ and is used in calculating properties such as density.

Unit cells are essential for interpreting crystal structure, predicting material properties, and indexing diffraction patterns. They are determined experimentally by diffraction methods and provide a compact description of the repeating arrangement that underpins crystalline materials.