. "Trioxygen"@en . . "Ozone /\u02C8o\u028Azo\u028An/ (systematically named 1\u03BB1,3\u03BB1-trioxidane and catena-trioxygen), or trioxygen, is an inorganic molecule with the chemical formula O3. It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope O2, breaking down in the lower atmosphere to normal dioxygen."@en . . . .