Walsh diagrams

The effect of bending the Ir—N—O linkage in the xz plane is shown in the Walsh diagram (Figure 2.105). 

Figure 2.105 Walsh diagram for an [IrCl4(NO)]2 system. (Reprinted with permission from Inorg. Chem., 1974,13, 2667. Copyright (1974) American Chemical Society.)...

Reference to the Walsh diagram (Figure 2.105) shows that for a MNO 8 system, bending produces a net stabilization, thus rationalizing the M—N—O bond angle of c. 120° found for systems like M(NO)Cl2(PR3)2. 

Charge Distribution, Electron Density Distribution and Walsh Diagrams 69,1166,1405,1697... 

A good deal of information on small radicals can be obtained from Walsh diagrams (77). These correlation diagrams allow the estimation of molecular geometry from the mere knowledge of the number of valence electrons. The procedure and arguments are similar to those presented by Mulliken (78), who discussed the shapes of ABl molecules in ground and excited states and interpreted their electronic spectra. 

For qualitative discussions, Walsh diagrams (see Sec. I.C.2.) have proved to be very useful, for example, in determining the structures of AB2, AB3, and HAAH molecules in ground and excited states. These correlation diagrams show how MO levels change on passing from one extreme molecular geometry to another. 

Although the complexity increases rapidly there is no reason that Walsh diagrams cannot be constructed for XY3 pyramidal, XY4 tetrahedral, XYS octahedral, and other molecules. In fact, they have been prepared, but their applications will not be described here. Insofar as these diagrams are amenable to quantitative interpretation, the predictions are in accord with what we know from experimental evidence and valence bond methods. 

Burdett has also applied the AOM to the rationalisation of the geometries of main group molecules (38). Correlation diagrams (analogous to Walsh diagrams) can be constructed to show the angular dependence of MO energies, and the shapes of simple... 

Walsh diagrams give rules only for the qualitative decision bent or linear If a molecule is bent, determination of the exact value of the bond angle requires a detailed calculation. 

Figure 9.4. Walsh diagram showing correlation of orhitals between bent and hnear triatomic molecules, and suggesting variation in orbital energy with bond angle.

Mo—Mo bond by adding one electron into this orbital might cause an increase in the metal-metal separation. This would result in the stabilization of the semi-occupied orbital, as shown by the Walsh diagram associated with the variations of the M02S2... 

Fig. 4.14 (a) The energy levels of the n states for a single free atom A, two non-interacting atoms B, and thetriatomic molecule AB2. (b) The Walsh diagram for the AB2 molecule. (After Williams (1979).)... 

The Walsh diagram shown m Fig. 6.16 is accurate only for molecules in which there is a large separation between the ns and np energy levels of the central atom. If the ns-np separation is small (as in SrF2 and BaFz). the lb2 level (of Fig. 6.16) does not rise as rapidly as 2a, fells, and the molecule may be stabilized on bending.26 Note that in MFa molecules of this type, the 3o, and I bt levels are unoccupied. 

Wacker process, 714-715 Wade s rules, 798, 805 Walden inversion, 243 Walsh diagrams, 218 Water, physical properties of. 360... 

Refer to the molecular orbital diagram for NOj in Fig. 5.31. Walsh diagrams, similar to those in Fig. 6.16, predict that the HOMO (oi) becomes more stable as the O—N—Obond... 

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