P„-d„ bonding

In [Cl3Sn(P02Cl2) P0Cl3]2 (type (IVa)) it decreases to 118° for example (77). The reason may be found in the ability of the P-Cl bond, to involve d c7 )-orbitals, and thus to relieve the p d ) bond, which induces a large OPO bond an e. Because of the energetically highly excited c7-levels of the fluorine ligands, the P-F bond can do this only to a very small extent. 

In InP Zn samples purposely neutralized by hydrogen, a sharp vibrational line is observed at LHeT at 2287.7 cm-1 shifting to 1664.5 cm-1 in deuterated samples (Pajot et al., 1989). The r-factor for these lines (1.3744) and the frequencies indicate that P—H or P—D bonds have been formed and that the neutralizing complex is presumably (P—H Zn). 

Tishinin, D.V., Dapkus, P.D., Bond, A.E., Kim, L, Lin, C.K., and O Brien, J., 1999, Vertical resonant couplers with precise coupling efficiency control fabricated by wafer bonding, IEEE Photon. Technol. Lett. 11(8) 1003-1005. 

It is important to point out that the covalent bond has many faces. They can range from simple s, p, d, bonds to sp- or spd- hybridization bonds which may result in a and ji bonds that form the building block for single, double, and triple bonds. In more complex cases they can be resonance bonds or multi-centered bonds that are often observed in metals and alloys. 

Phosphonium ions exchange with acidic deuterium sources to form P—D bond-containing products. Alkylphosphoniums react with D O as ... 

The barrier to pyramidal inversion at arsenic in isopropylphenyltrimethylsilylarsine (165) is ca 74 kJ moP lower than in 11, whereas the less electronegative trimethylgermyl substituent reduces the barrier by ca 66 kJ mol Thus, the most important influence on pyramidal stability in these systems appears to be the atomic electronegativity of the adjacent heteroatom and not p -d bonding as had been suggested earlier as the source of barrier lowering in (R, R )/(R, S )-l,2-dimethyl-l,2-dipheny arsine (166) ". ... 

Ab initio calculations on PF5 and on a variety of substituted fluorophosphor-anes assign a significant role to p -d bonding and support the BPR route for ligand exchange in PFs and in PF3H2. 

For an earlier similar conclusion based on the poor correlation between the ionization potential of X and the difference between >(Me3Si-X) and D(Me-X) see B. G. Gowenlock and J. Stevenson, J. Organomet. Chem., 13, PI3 (1968). This paper challenges an earlier conclusion that (p-d) bonding is important, see S. J. Bond, I. M. T. Davidson and C. A. Lambert, J. Organomet. Chem., 12, P3 (1967). See also Refs. 63-67. 

This has been rationalized by Kruck (152) who suggested that the F P p -d bond in uncoordinated PF3 is strengthened slightly when the ligand becomes coordinated to a zero-valent metal. The donor a bond leads to a decrease in the electron density at phosphorus, but this is opposed by d -d bonding from metal to phosphorus. 

It must be noted that the importance of p-d bonding with d orbitals of second-row atoms has been questioned on theoretical grounds (146). 

The importance of the dipolar structure is due to the inherent weakness of the p - d bond between phosphorus and... 

---