anion vacancy

A type of point defect in a crystal lattice, specifically categorized as part of a Schottky defect, which involves a pair of missing positive (cation) and negative (anion) ions to maintain charge neutrality, or as part of a Frenkel defect, where an ion moves to an interstitial site leaving a vacancy. If the vacancy is filled by an electron, it's known as an F-center (Farbzentrum), creating a color center.