Po-X bonds

The broken bonds (boldface = dissociated atom or group) 

Note (1) The data of S-0 bonds see the O-S bonds in Chapter 6. (2) The data of S-N bonds see the N-S bonds in Chapter 7. (3) The BDEs in the clusters and complexes of C-, Si-, Ge-, Sn-, and Pb-ions are listed in Chapter 24. (4) The BDEs in the clusters and complexes of N-, P-, As-, Sb-, and Bi-ions are listed in Chapter 25. (5) The BDEs in the clusters and complexes of 0-, S-, Se-, Te-, and Po-ions are listed in Chapter 26. (6) The BDEs in the clusters and complexes of halogenated ions are listed in Chapter 27. 

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The lower electronegativities of the S—Po elements lessen the ionic character of compounds that are formally analogous to those of oxygen, alter the relative stabilities of various kinds of bonds, and drastically lessen the importance of hydrogen bonding, although weak X—H - S and S—H—X bonds do exist. 

X=F,C ,Br,I) has been prepared and structurally characterized (Section 7). It has been suggested that considerable PO xr bonding occurs.The reaction of NjPjCf with sodium 2,6-(ditertbutyl)phenoxide NaOR gives, at least two products,... 

In Eig. 20.11 we compare the structures of PF3 and PCI3 with the sfructures of the corresponding phosphoryl trihalides, OPX3. Both the PO bond distances and the thermochemical bond energies calculated by transfer of the P-X bond energies from the trihalides, indicate that the PO bonds are best described as double. 

The ionic method has been used in MM calculations on complexes of Fe(III) , the alkali and alkaline earth cations, and the lanthanides. Unlike the VFF and POS methods, structures and energies calculated with the ionic method are extremely sensitive to the van der Waals parameters and the charge assigned to the metal and the ligand atoms. With the omission of interactions used in bonded methods, the ionic model has failed in some cases to accurately reproduce structural features such as L-M-L and M-L-X bond angles and M-L-X-X torsional interactions. ... 

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