page_title: Schottky defect
section_title: Illustration
hierarchical_section_title: Schottky defect / Illustration
caption_attribution_description: Русский: Структура кристалла NaCl
context_page_description: A Schottky defect is an excitation of the site occupations in a crystal lattice leading to point defects named after Walter H. Schottky. In elemental crystals it refers to simple lattice vacancies, also called valency defects. In ionic crystals, this defect forms when oppositely charged ions leave their lattice sites and become incorporated for instance at the surface, creating oppositely charged vacancies. These vacancies are formed in stoichiometric units, to maintain an overall neutral charge in the ionic solid.
context_section_description: Chemical equations in Kröger–Vink notation for the formation of Schottky defects in TiO₂ and BaTiO₃. 
  ∅ ⇌ v
  Ti  + 2 v••
  O
  ∅ ⇌ v
  Ba  + v
  Ti  + 3 v••
  O
  This can be illustrated schematically with a two-dimensional diagram of a sodium chloride crystal lattice:
caption: The defect-free NaCl structure
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