Crystal structure is the arrangement of atoms or molecules in the solid state that involves consideration of defects, or abnormalities, in idealized atomic/molecular arrangements. The three-dimensional aggregation of unit cells in the crystal forms a space lattice or Bravais lattice. This article provides a brief review of the terms and basic concepts associated with crystal structures. It also discusses some of the significant defects obstructing plastic flow in real crystals, namely point defects, line defects, stacking faults, twins, and cold work. Several tables in the article provide information on the crystal structures and lattice parameters of allotropes of metallic elements.

This article defines crystallographic terms and concepts, including crystal structure, unit cell, structure symbols, lattice, space-group notation, and atom position. It schematically illustrates the atom positions, prototypes, structure symbols, space-group notations, and lattice parameters for some of the simple metallic crystals. A table that lists the crystal structures of various metal elements is presented. The crystal structures are described by the Pearson symbols for crystal system, space lattice, total number of atoms per unit cell, and prototype structure. The article tabulates the assorted structure types of metallurgical interest arranged according to Pearson symbol. It also provides information on crystal defects, explaining some significant ones, such as point defects, line defects, stacking faults, and twins.

This article presents a table of the crystal structure of allotropic forms of metallic elements in terms of the Pearson symbol, space group, and prototype of the structure. The temperatures of the phase transformations are listed in degree Celsius and the pressures are in GPa. The lattice parameters of the unit cells are given in nanometers. The compilation of the table is restricted to changes in crystal structure that occur as a result of a change in temperature or pressure.

The crystal structure of a material is an important aspect of corrosion and oxidation processes. This article provides a general introduction to the crystal structure of materials, providing information on the crystal systems, lattice dimensions, nomenclature, and solid-solution mechanisms used to characterize structures. It illustrates the unit cells and ion positions for some simple metal crystals, arranged alphabetically according to the Pearson symbol. The space lattice and crystal system, space-group notation, and prototype for each crystal are also illustrated.

This article describes crystallographic terms and concepts and illustrates various crystal structures. The crystallographic terms described include crystal structure, unit cell, crystal system, lattice, structure symbols, space-group notation, structure prototype, atom positions, point groups, and equivalent positions. The article presents a table of assorted structure types of metallurgical interest arranged according to the Pearson symbol. It also schematically illustrates atom positions, prototypes, structure symbols, space-group notations, and lattice parameters for some of the simple metallic crystals. The article concludes with a description of some of the most significant crystal defects such as point defects, line defects, and stacking faults.

Pure metals normally solidify into polycrystalline masses, but it is relatively easy to produce single crystals by directional solidification from the melt. This article illustrates the dislocations present in a metal crystal, which is often polygonized into sub-boundaries during grain growth after solidification. It provides a description of small-angle and large-angle grain boundaries of polycrystalline metals.