Matrix Reactions of Oxygen Atoms with P4. Infrared Spectra of P4O, P2O, PO and PO2

Article abstract of DOI:10.1021/ja00225a001

Oxygen atoms (16O and 18O) from ozone photolysis and discharge of oxygen molecules were reacted with P4 molecules and the products were trapped in solid argon at 12 K.The major product P4O exhibited a strong terminal P=O stretching mode at 1241 cm^-1, a P-P=O deformation mode at 243 cm^-1, and four P-P stretching modes near P4 values, all of which characterize a C_3v species.Two new molecular species probably arise from energized P4O before relaxation by the matrix: The first absorbed at 1197 cm^-1, photolyzed with red light, and is probably P2O.The second absorbed at 856 and 553 cm^-1, increased with short-wavelength radiation, and is most likely due to the C_2v bridge-bonded P4O structural isomer.Higher discharge power gave O atoms and vacuum ultraviolet radiation; these conditions favored the bridge-bonded P4O species and the simple PO and PO2, which were observed at 1218 and 1319 cm^-1, respectively.The matrix efficiently quenched the large exothermicity (130 +/- 10 kcal/mol) for the P4 + O reaction and allowed the lowest oxide of phosphorous, P4O, to be trapped for the first time as a molecular species.