4 ) , both of which are dangerously explosive and powerful oxidizing agents , and xenon dioxide ( XeO2 ) , which was reported in 2011 with a coordination number of four . XeO2 forms when xenon tetrafluoride is poured over ice . Its crystal structure may allow it to replace silicon in silicate minerals . The XeOO + cation has been identified by infrared spectroscopy in solid argon .