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Congeneric Array Database

Congeneric arrays are isoelectronic sets of chemical species with linear structure and reactivity behaviour traits. More than 100 congeneric series and planars have been collected together, along with some other interesting collections of chemical species that are not congeneric.

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pi-Systems, Linear (1)

The linear pi-system series is constructed from two alternating series depending upon whether a pi-system has an even or an odd number of conjugated (adjacent) p orbitals.
• Species with an odd number of p orbitals (1p orbital, 3p orbitals and 5p orbitals) present as reactive anions, radicals or cations and they have an MO topology in which the same MO acts as the HOMO, SOMO and LUMO.
• Species with an even number of p- orbitals (2 p orbitals and 4 p orbitals etc) are neutral species and they have different HOMO and LUMO topologies.

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The Emergence of Organic Chemistry The Five Reaction Chemistries

© Mark R. Leach 1999 –

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