Ligand group orbital

Table 6-3. Labelling of metal and ligand group orbitals in O symmetry.

Symmetry Metal orbital Ligand group orbital... 

The three-fold degenerate set of p orbitals are labelled tiu t for three-fold, u for odd under inversion through the centre of symmetry). As shown in Fig. 6-6, each metal p orbital matches symmetry with ligand group orbitals comprising just two... 

To illustrate this point, the contributions of the occupied molecular orbitals to the total electron density at the nucleus are summarized in Table 5.2 for Fep4 (S - 5/2). It is evident from the table that the contributions coming from the orbitals at —6,966 eV must be assigned to the iron Is orbital, those from orbitals at —816 eV to the iron 2s orbital, and those from orbitals at —95 eV to the iron 3s orbital. In this highly symmetric complex, only two valence orbitals contribute to p(0), i.e. the —25 eV contribution from the totally symmetric ligand-group orbital that is derived from the F 2s orbitals and the —1 eV contribution from the totally symmetric... 

In a similar way, we obtain the wave functions for combinations of ligand group orbitals with the py and pz orbitals from the metal ion. They can be written as... 

When we inspect the dxi 2 orbital, we see that the lobes have positive signs in the x direction and negative signs in the y direction as shown in Figure 17.15f. The ligand group orbitals that match the symmetry of the dx> 2 orbital will be... 

Orbitals on metal Molecular orbitals Ligand group orbitals... 

In order to actually participate in a u bond within the complex, a metal orbital must be capable of positive overlap with a ligand group orbital directed along the bonding axes. For the moment, let us merely consider the directional requirement and... 

Fig. 11.18 Identification of the symmetries of ligand group orbitals and metal orbitals involved in the o bonds (represented as vectors) of an octahedral MU. complex. The characters of the reducible representation, r, are derived by counting the number of vectors that remain unmoved under each symmetry operation of the Oi, point group The irreducible components of C, are obtained by application of Eq. 3.1-...

Fig. 11.19 Ligand group orbitals (LGOs) and symmetry-matched metal atomic orbitals appropriate for a bonding in an octahedral ML complex.

The ligand group orbitals capable of tt interactions in an octahedral complex fall into four symmetry categories (Fig. 11.24) t2k, ttl l- , and Of these, a transition metal will possess Orbitals of only two of the types (dxvt dxt, and d ) and ilu (px, py, and pt). Conceivably, the metal could use all of these orbitals for tt bonds. However, the members of the /lu set are directed towards the ligands and therefore participate in strong c bonds. Formation of tt bonds using these orbitals would tend to... 

Fig. 11.24 Identification of the symmetries of ligand group orbitals and metal orbitals capaMf of participating in ir bonds (represented na vectors) in an octahedral Ml complex. The characters and irreducible components of the reducible representation, T,. were derived by application of the same methods used for the c-only system (Fig. 11.(8).

Fig. 15.32 Ligand group orbitals. md matching. uomic oihil.th on m>n for lerrocune.

Figure 6.11 The a ligand group orbitals (LGOs) for an octahedral complex, [MLg]...

Ligand field theory 11 Ligand group orbitals 115... 

The ligand group orbitals capable of ir interactions in an octahedral complex fall into four symmetry categories (Fig. 11.24) r, and Of these, a transition... 

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