[2] There is evidence that tiny quantities of cyclic ozone exist at the surface of magnesium oxide crystals in air.

[3] Cyclic ozone has not been made in bulk, although at least one researcher has attempted to do so using lasers.

[4] Another possibility to stabilize this form of oxygen is to produce it inside confined spaces, e.g., fullerene.

[5] It has been speculated that, if cyclic ozone could be made in bulk, and if it proved to have good stability properties, it could be added to liquid oxygen to improve the specific impulse of rocket fuel.

[4] Currently, the possibility of cyclic ozone is confirmed within diverse theoretical approaches.