Vacancy defect

A vacancy defect is a point defect in a crystal lattice where an atom or ion is missing from a normally occupied site. It disrupts local coordination and can influence diffusion and material properties.

Point defect: A localized disruption of a crystal lattice involving one or a few atomic sites. Vacancies are one of the principal point-defect types.
Crystal structure: The ordered arrangement of atoms, ions, or molecules in a crystalline solid. A vacancy is defined by the site missing from this periodic arrangement.
Ionic conductivity: The ability of a material to carry electric current through the motion of ions. Vacant sites provide pathways for ions to move through many solid electrolytes.
Interstitial defect: A point defect in which an extra atom or ion occupies a normally unoccupied position in a crystal. An interstitial adds a particle, whereas a vacancy leaves a lattice site empty.
Vacancy formation energy: The energy required to create a vacancy in a crystal under specified conditions. It helps determine the equilibrium concentration of vacancies.
Lattice site: A position in a crystal lattice associated with a regularly repeated atomic or ionic location. The missing particle would normally occupy a lattice site.
Solid-state battery: A battery that uses a solid electrolyte rather than a liquid electrolyte. Vacancy-mediated ion transport can determine solid-electrolyte performance.
Substitutional defect: A point defect in which an atom or ion replaces a different species at a lattice site. A substitution changes the occupant of a site rather than leaving it empty.
Vacancy diffusion: Atomic transport in a crystal through successive jumps into neighboring vacant lattice sites. A vacancy moves through the lattice as neighboring atoms fill it.
Coordination number: The number of nearest neighboring particles surrounding a specified particle or site. Removing an atom changes the local coordination around its former site.

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Isomorphous substitutionCompared with: A vacancy leaves a site empty instead of filling it with a substitute ion.