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The Hückel method or Hückel molecular orbital theory, proposed by Erich Hückel in 1930, is a simple method for calculating molecular orbitals as linear combinations of atomic orbitals. The theory predicts the molecular orbitals for π-electrons in π-delocalized molecules , such as ethylene , benzene , butadiene , and pyridine .
Möbius (left) and Hückel (right) orbital arrays. The two orbital arrays in Figure 3 are just examples and do not correspond to real systems. In inspecting the Möbius one on the left, plus–minus overlaps are seen between orbital pairs 2-3, 3-4, 4-5, 5-6, and 6-1, corresponding to an odd number (5), as required by a Möbius system.
He is mainly known for the Debye–Hückel theory of electrolytic solutions and the Hückel method of approximate molecular orbital (MO) calculations on π electron systems. Hückel was born in the Charlottenburg suburb of Berlin. He studied physics and mathematics from 1914 to 1921 at the University of Göttingen.
In contrast to the rarity of Möbius aromatic ground state molecular systems, there are many examples of pericyclic transition states that exhibit Möbius aromaticity. The classification of a pericyclic transition state as either Möbius or Hückel topology determines whether 4N or 4N + 2 electrons are required to make the transition state aromatic or antiaromatic, and therefore, allowed or ...
the molecule must have 4n + 2 (a so-called "Hückel number") π electrons [7] (2, 6, 10, ...) in a conjugated system of p orbitals (usually on sp 2-hybridized atoms, but sometimes sp-hybridized); the molecule must be (close to) planar (p orbitals must be roughly parallel and able to interact, implicit in the requirement for conjugation);
[7] [8] [9] A program for the extended Hückel method is YAeHMOP which stands for "yet another extended Hückel molecular orbital package". [ 10 ] YAeHMOP has also been merged with the Avogadro open-source molecular editor and visualizer to enable calculations directly from the Avogadro graphical user interface for materials that are periodic ...
Hückel or Huckel may refer to: Erich Hückel (1896-1980), German physicist and chemist ... This page was last edited on 27 January 2019, at 17:30 (UTC).
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