This is the fourth member of the polyoxidanes. The first three are water [(mon)oxidane], hydrogen peroxide (dioxidane), and trioxidane. Tetroxidane is more unstable than the previous compounds. The term "tetraoxidane" extends beyond the parent compound to several daughter compounds of the general formula , where R can be hydrogen, halogen atoms, or various inorganic and organic monovalent radicals. The two Rs together can be replaced by a divalent radical, so heterocyclic tetroxidanes also exist.