Spinel structure

The spinel structure is a common crystal structure of the AB type composition ₂O₄ where A is a cation on a tetrahedral site (surrounded by 4 oxygens) and B, two cations on octahedral sites (surrounded by de 6 oxygens). This type of compact cubic structure is flexible and stable over a wide range of pressures and temperatures. Well known minerals having this spinel structure include spinel MgAl₂O₄, magnetite Fe₃O₄, chromite FeCr₂O₄, and ringwoodite SiMg₂O₄.