Dsp hybrid orbitals

Figure 6-13. Synergic back-bonding in a platinum alkene complex. In (a), the interaction of a (filled) platinum 5d orbital with the tf molecular orbital of the alkene is shown, whilst in (b), the interaction of a dsp hybrid orbital with the n molecular orbital of the alkene is shown. Note that the two interactions result in electron density moving in opposite directions.

The range of isomer shifts is larger for aurous, Au(l), than for auric, Au(lll), compounds, most probably due to the larger amount of -character in sp than in dsp hybrid orbitals, and also to the smaller variety of ligands in the auric compounds under study. 

Complexes of class a metals are more ionic, while those of the class b metals are more covalent. Generally, the metals that form tetrahedral complexes by using sp hybrid orbitals are class a types. Those forming square planar complexes by using dsp hybrid orbitals are normally class b types. 

Most hybridizations result in equivalent hybrid orbitals, i.e., all the hybrid orbitals are identical in composition (% s and % p character) and in spatial orientation with respect to each other. They have very high symmetries, culminating in tetrahedral and octahedral symmetry. In the case of dsp hybrid orbitals, the resulting... 

Formation of a cr-bond by donation from the ir-orbital of ethene into a vacant metal dsp hybrid orbital... 

Of great importance is the nature of surface bonding of intermediates to the metal this depends very much on the geometry and orientation of the crystal plane on which the chemisorption takes place, and on the orientation and symmetry of emergent orbitals (especially dsp hybrid orbitals at transition metal surfaces) at the metal surface as emphasized and illustrated by Bond (24, 7) (Fig. 5 A). These factors determine the geometry of coordination of the adspecies at the catalyst or electrocatalyst surface. Since that work (41), a great many papers have appeared on molecular-orbital calculations for bonding at surfaces and on surface states and electron-density distributions. 

We construct the first set of hybrid orbitals from one s atomic orbital, the three p atomic orbitals and the d atomic orbital they are called dsp hybrid orbitals. The principal quantum numbers of the participating atomic orbitals depend on the particular metal atom under consideration for Co, they would be the 3d, 4s, and 4p atomic orbitals. The dsp hybrid orbitals in the most general case are written out as... 

As shown in Figure 8.30a, these orbitals point to the vertices of a trigonal bipyramid there are three equivalent equatorial hybrids and two eqnivalent axial hybrids. Examples of molecules whose shapes are described by dsp hybridization inclnde PF5, which you have seen in Section 3.9, and CnCl C PF5 is shown in Fig-nre 8.30b for comparison with the set of dsp hybrid orbitals. 

Square Planar Complexes Metal ions with a d configuration usually form square planar complexes (Figure 22.13). In the [Ni(CN)4] ion, for example, the model proposes that one 3d, one 4j, and two Ap orbitals of Ni mix and form four dsp hybrid orbitals, which point to the comers of a square and accept one electron pair from each of four CN ligands. 

A set of dsp hybrid orbitals on a phosphorus atom. Note that the set of five dsp orbitals has a trigonal bipyramidal arrangement. (Each cfsp orbital also has a small lobe that is not shown in this diagram.)... 

The hybrid orbitals required on a metal ion in a four-coordinate complex depend on whether the structure is tetrahedral or square planar. For a tetrahedral arrangement of ligands, any/7 hybrid set is required (see Fig. 21.19). For example, in the tetrahedral CoCl4 ion, the Co can be described as sp hybridized. A square planar arrangement of ligands requires a dsp hybrid orbital set on the metal ion (see Fig. 21.19). For example, in the square planar Ni(CN)/ ion, the Ni is described as dsp hybridized. 

The trans influence of a ligand is the ability of a ligand to weaken the bond trans to itself in a complex. Gold(I) and gold(III) complexes are, in the simplest treatment, considered to use sp and dsp hybrid orbitals in forming linear and square planar complexes respectively. A good o donor, L, tends to concentrate gold 6s character in the AuL bond and the trans bond must then overlap with an orbital of low s character. A weaker and more ionic bond is then formed. 

Although it will not be important for our purposes, the dsp hybrid orbital set is different from the hybrids we have considered so far in that the hybrid orbitals pointing to the vertices of the triangle (often called the three equatorial hybrid orbitals) are slightly different in shape than the other two (the axial orbitals). This situation stands in contrast to the sp, sp, and sp hybrid sets in which each orbital in a particular set is identical in shape to the others. 

Use the projection operator method to determine the mathematical forms of the five dsp hybrid orbitals. 

Figure 13.31 shows models showing d sp and dsp hybrid orbitals. Note the identical shapes of the hybrid orbitals and their arrangement to match the observed geometries. The bonding in sulfur (vi) fluoride, SFg can also be described using d sp hybridization. 

The structure shown in Figure 10 can be explained using dsp hybridization in Fe atom. AH eight electrons present in the valence shell of Fe atom (Fe 3d 4s ) get paired in four 3d orbitals. Thus, the valence shell configuration of Fe in Fe(CO)s becomes 3d 4s°. The OC Fe bond results by the overlap between the empty dsp hybrid orbitals on Fe atom and the HOMO on C atom in a CO molecule, as shown in Figure 11. 

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