Keywords: Connelly-Orpen-PR3-pi-acceptor-orbitals.png Sketch of the linear combination of P “C and P 3d orbitals in phosphines PR<sub>3</sub> to form -acceptor molecular orbitals for pi backbonding in metal-phosphine complexes R<sub>3</sub>P “M Based on diagrams in http //dx doi org/10 1021/om00118a048 A G Orpen N G Connelly Organometallics 1990 9 1206 “1210 Image generated in http //www cambridgesoft com/software/ChemBioDraw/ ChemBioDraw Ultra 12 0 Own 2012-02-05 Ben Mills Benjah-bmm27 Images by Ben Mills Pi backbonding |