P406 was reacted with oxygen atoms (I6O and" 0) obtained from ozone photolysis and discharge of oxygen. The P407-10 and P40618014 products were trapped in solid argon and examined by infrared spectroscopy. The spectra of the four higher oxides support a central P406 cage structure with additional terminal P== I6O or P= IaO bonds. The P== I6O and vibrations are identified in four higher oxides, and assignments are proposed for ...