Orgel diagrams

Orgel diagrams Simple graphs showing the relation between the energies of various electronic slates and the crystal field splitting. 

Figure 3-21. Orgel diagram for energies of octahedral or tetrahedral terms arising from free-ion D terms.

FIGURE 18.2 An Orgel diagram for metal ions having D spectroscopic ground states. The multiplicity of the D state is not specified because it is... 

The Orgel diagram for tetrahedral nickel(II), shown in Fig. 8, is similar to that for the octahedral case, but the levels are inverted. The lowest level, 3Ti(P), has the same symmetry properties as the higher level 3Ti(P), and the two influence each other therefore, since all transitions are from 3Ti(F), no transition corresponds to the splitting A. To a first approximation the transition energies should be given by 0.8 A, 1.8 A, and (3P — 3F) + 0.6 A 120). A is much smaller than in the octahedral case and the first transition, to 3Ti, lies in the far infrared and has not been observed. 

Furlani and Morpurgo (98) have, however, obtained very good spectra of the complex anions in nitromethane addition of a small excess of halide was necessary in most cases. Their results are summarized in Table VI, together with the assignment in a regular tetrahedral field. The symbols used may be understood by reference to the Orgel diagram of Fig. 8. 

Fig. 11.40 Orgel diagram for d, d1, cl7, and d ions in octahedral and teirahedral fields. [From Lever. A. B. P. Inorganic Electronic Spectroscopy, 2nd ed. Elsevier. New York. 1986 p 85. Used with permission.)...

Figure 108 Copper(III) ion (a) Orgel diagram and (b) the electronic spectrum of [CuF6]3 anion1347...

The foregoing results for d1, high-spin d4 and d6, as well as d9 octahedral complexes can be summarized by the fairly simple Orgel diagram shown in Fig. 8.5.2. 

Additionally, we note that octahedral and tetrahedral complexes have opposite energy orderings (Fig. 8.1.5). Hence d1 octahedral and d9 tetrahedral have the same Orgel diagram the same is true for d6 octahedral and d4 tetrahedral complexes. In other words, the Orgel diagram in Fig. 8.5.2 is also applicable to d1, d4, d6, and d9 tetrahedral complexes. Since tetrahedral complexes are not centrosymmetric, their states do nothave g or u designations. States in Fig. 8.5.2 do not carry subscripts they should be put back on for octahedral complexes. 

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