Iron energy level diagrams

Fig. 30. Energy level diagrams for trigonal bipyramidal chromophores of iron(II)...

Figure 8.20 An energy level diagram for ferrocene. The MO energies are those calculated by Shustorovich and Dyatkina, using a self-consistent field procedure. The positions of the ring and iron orbitals on this diagram are only approximate.

Other Bis-cyclopentadienyl Compounds.—It is interesting to give similar accounts of other neutral molecules like ferrocene, where the central iron atom is replaced by Co, Ni, Cr or other atoms of the transition elements. The energy level diagram will not be veiy different from Fig. 11 in all these cases, and we may treat the molecules by adding, or subtracting the requisite number of electrons. 

Figure 3.16 Energy level diagram for ferric iron matched to spin-forbidden crystal field transitions within Fe3+ ions, which are portrayed by the polarized absorption spectra of yellow sapphire (adapted from Ferguson Fielding, 1972 Sherman, 1985a). Note that the unassigned band at -17,600 cm-1 represents a paired transition within magnetically coupled Fe3+ ions located in adjacent face-shared octahedra in the corundum structure.

The procedure for calculating energy level diagrams by the self-consistent field Xa scattered wave (SCF-Xa-SW) method is as follows (Sherman, 1984, 1991). An octahedral cluster such as [FeO6]10 is partitioned into a set of (overlapping) spheres centred about divalent iron and each oxygen atom, and these are surrounded by an outer sphere. Within each atomic sphere the one-electron Schrodinger equation... 

Figure 11.6 Molecular orbital energy level diagrams computed for iron octahedrally coordinated to oxygen. Left divalent iron in the [Fe06]-1° cluster (based on Sherman, 1991) right trivalent iron in the [Fe06]-9 cluster (from Sherman, 1985a). Orbital energies have been scaled relative to zero for the non-bonding 6rlu level.

Fig. 4.27. Molecular-orbital energy-level diagram for the (FeO,) " cluster calculated using the MS-SCF-Jfa method. The highest-energy occupied orbital is the 2 2g i containing one electron. Also shown are the energies of Fe and O atomic orbitals. Spin-up (f ) and spin-down ( i ) molecular orbitals are shown in this spin-unrestricted calculation on a regular octahedral (O ) cluster at an iron-oxygen distance of 2.17 A (after Tossell et al., 1974 reproduced with the publisher s permission).

Fig. 6.6. Energy-level diagram to illustrate the electronic structure of iron-bearing sphalerite and based on MS-SCF-A a cluster calculations on the FeS/ tetrahedron (after Vaughan et al., 1974). Discrete MO energy levels (spin up,, and spin down, i ) are shown on the right on the left is a simplistic band model based on this, with filled (or partly filled) bands shown shaded (lines crystal-field-type band dots sulfur nonbonding band dashes metal-sulfur bonding band).

Fig. 8.25. A qualitative molecular-orbital energy-level diagram for pyrite, drawn to illustrate the possible interaction between 3d orbitals on iron and empty orbitals of IT symmetry on sulfur (after Burns and Vaughan, 1970, reproduced with the permission of the publisher).

Fig. 8. Energy level diagram for Pyridine-Co complexes of iron(II) porphine, chlorin, iBC and BC (Taken from Ref. 93)...

Draw an orbital energy-level diagram for CN. Start by combining 2p orbitals on C and N, and then consider whether you need to include other orbitals. (The energy of the N 2p orbital lies between those of C 2p and C 2s. That of the N 2s is much lower than C 2s.) CN is known only from spectroscopic studies, but the cyanide ion CN is very well known. With which molecule discussed in this Section is it isoelectronic Does molecular orbital theory suggest that CN- might bind to iron ... 

Fig. 8. Calculated d orbital energy level diagram for Fe(ll) in a series of ligand fields. Iron is represented as a filled sphere and ligands as open spheres.

While the energy level diagrams and the corresponding spectroscopic transitions are relatively straightforward for light elements, they become very complex for heavier elements. The number of observed Hnes listed by Harvey [3] increases from the alkah metals with 30 (for lithium) to 645 (for caesium) to several thousand lines for the transition elements (chromium 2277, iron 4757, and cerium 5755 lines, respectively). 

The electronic structures of iron, cobalt, nickel, and the platinum metals are given in Table 19-1, as represented in the energy-level diagram of Figure 5-6. It is seen that each of the atoms has two outermost electrons, in the 4s orbital for iron, cobalt, and nickel, the 55 orbital for ruthenium. 

A Hiickel molecular orbital calculation for the cyclopentadiene system can be carried out as illustrated in Chapter 5. As is shown in Figure 5.20, the Frost-Musulin diagram places the five molecular orbitals at energies of a + 2/3, a + 0.618/3 (2), and a — 1.618/3 (2). Because the cyclopentadienyl anion has six electrons, only the three lowest energy levels are populated and are the orbitals interacting with those on the iron. Figure 21.15 shows the orbitals of the cyclopentadienyl anion. 

Fig. 3.8. The crystal Held derived orbital splitting diagram for a high spin octahedral iron(II) 34 complex (o), and the corresponding energy level and spectroscopic state diagram (b).

Iron is in the same group in the periodic table as ruthenium. Construct the orbital diagram (using the arrow-in-box notation) for iron, showing the electrons in the n = 3 and n = 4 energy levels and label each sub-level on the diagram. 

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