kristallstruktuuri

Kristallstruktuuri, or crystal structure, refers to the ordered arrangement of atoms, ions, or molecules in a crystalline material. It is defined by a repeating pattern that extends in three spatial dimensions. The structure can be described as a lattice—an infinite array of points—and a basis, the collection of atoms associated with each lattice point. The combination yields a unit cell, the small building block that repeats to form the crystal through translations.

In three dimensions, crystals are classified into seven crystal systems (cubic, tetragonal, orthorhombic, trigonal, hexagonal, monoclinic, triclinic) and, more precisely, into 14 Bravais lattices, describing distinct ways to arrange lattice points. The full symmetry of a crystal is captured by its space group, which includes rotational, mirror, and translational symmetries.

Crystal structure influences material properties. Lattice parameters and atomic arrangements determine density, mechanical strength, electronic structure, and optical behavior. Defects such as vacancies, interstitials, and dislocations, as well as phase transitions, can modify properties.

Structures are determined experimentally mainly by diffraction methods, especially X-ray diffraction, with neutron and electron diffraction providing complementary information. Analysis yields lattice parameters, atom positions, and the space group, enabling models for materials and minerals.