Phosphine oxide

"Phosphine oxides are phosphorus compounds with the formula OPX₃. When X = alkyl or aryl, these are organophosphine oxides. Triphenylphosphine oxide is an example. An inorganic phosphine oxide is phosphoryl trichloride (Cl₃PO). Such compounds are thermally stable, decomposing only above 450 °C.^[1] Phosphoryl refers to a functional group drawn with a phosphorus-oxygen double bond."

"According to Molecular Orbital Theory, the short P-O bond is attributed to the donation of the lone pair electrons from oxygen p-orbitals to the antibonding phosphorus-carbon bonds; In Valence Bond terms this means having a P=O double bond and a delocalized four-center six-electron P-Cl system occupying two orbitals. This proposal, which is supported by ab initio calculations, has gained consensus in the chemistry community."

"The nature of the phosphorus to oxygen bonding was once hotly debated, as the involvement of a phosphorus d-orbitals in bonding is not supported by computational analyses. In terms of simple Lewis structure, the bond is more accurately represented as a dative bond, as is currently used to depict an amine oxide."