Organ diagram
Organ diagrams are correlation diagrams introduced by Leslie Orgel (British chemist, 1927-2007) , which plot the term energies in transition metal complexes as a function of the splitting energy, similar to Tanabe-Sugano diagrams .
Organ diagrams are limited to high-spin complexes and do not provide information about low-spin complexes. Since the diagrams are qualitative, no energy calculations can be made from these diagrams. In contrast to a Tanabe-Sugano diagram, organ diagrams also show only the symmetry states of the highest spin multiplicity instead of all possible terms. Organ diagrams, however, show the number of spin-allowed transitions along with their respective symmetry drawings.
In an organ diagram, the main term (P, D or F) is in the middle of the diagram in the absence of a ligand field. There are two organ diagrams, one for configurations d 1 , d 4 , d 6 and d 9 (D organ diagram) and the other for configurations d 2 , d 3 , d 7 and d 8 (P- and F-organ diagram).
D organ diagram
For ions with one of the configurations d 1 , d 4 , d 6 or d 9 , the D organ diagram shows that the D basic term is split into a T 2 (g) and an E (g) term . With increasing field strength, i.e. starting from the middle of the diagram to one of the two sides, their energetic distance increases. On the left of the diagram there are the d 1 or d 6 tetrahedra and the d 4 and d 9 octahedra, correspondingly the d 4 or d 9 tetrahedra and the d 1 and d 6 are found on the right in the diagram . Octahedron.
P and F organ diagram
For ions with the configuration d 2 , d 3 , d 7 or d 8 , the P- and F-organ diagrams show that the F-basic term turns into a T 2 (g) -, T 1 (g) - and splits an A 2 (g) term, while the P ground term converts to a T 1 (g) term. With increasing field strength, i.e. starting from the middle of the diagram to one of the two sides, the energetic distance between them also increases here. On the left of the diagram there are the d 2 or d 7 tetrahedra and the d 3 and d 8 octahedra, correspondingly the d 3 or d 8 tetrahedra and the d 2 and d 7 are found on the right in the diagram . Octahedron.
The electron configuration d 5 has no spin-allowed transitions and therefore no dd-transitions are to be expected in a UV-Vis absorption spectrum (a spin-forbidden transition with very weak intensity is nevertheless observed).
Individual evidence
- ^ A b c d Catherine E. Housecroft, Alan G. Sharpe: Inorganic Chemistry . 4 ed.Pearson Prentice Hall, Harlow, England 2012, ISBN 978-0-273-74275-3 , pp. 691-693 .
- ↑ a b c d Riedel, Erwin; Janiak, Christoph; Meyer, Hans-Jürgen: Modern inorganic chemistry . 4th edition. De Gruyter, Berlin 2012, ISBN 978-3-11-024901-9 , pp. 456 .