Path: csiph.com!aioe.org!newsfeed1.swip.net!uio.no!news.tele.dk!news.tele.dk!small.news.tele.dk!newsfeed-00.mathworks.com!nntp.TheWorld.com!.POSTED!not-for-mail From: moroney@world.std.spaamtrap.com (Michael Moroney) Newsgroups: sci.physics Subject: Re: Benzene ring- nothing has to magically "delocalize" Date: Thu, 30 Jul 2015 15:01:06 +0000 (UTC) Organization: The World : www.TheWorld.com : Since 1989 Lines: 42 Message-ID: References: <64c78a42-fd20-4aa6-a805-ce78dad4209d@googlegroups.com> <55413ca5-be7f-4d90-9e91-06ae1d1e0231@googlegroups.com> <33e3fc23-6fe8-489a-8952-77deae422008@googlegroups.com> <89c4ad48-e7ee-4817-81c4-082d907b79e8@googlegroups.com> <6494b4a2-a342-4f76-baf3-321ec45f9ee0@googlegroups.com> NNTP-Posting-Host: shell01.theworld.com X-Trace: pcls7.std.com 1438268466 669 192.74.137.71 (30 Jul 2015 15:01:06 GMT) X-Complaints-To: abuse@TheWorld.com NNTP-Posting-Date: Thu, 30 Jul 2015 15:01:06 +0000 (UTC) User-Agent: nn/6.6.5 Xref: aioe.org sci.physics:510337 john writes: >Michael said >"Or, even better, contribute an electron to a common bond with 5 other >atoms. " >Well, I never learned about "common >bonds". I learned that it takes 2 >electrons to fill an orbital. That's generally true, but what happens is more complicated than that simplification. The following description is probably wasted on you, but perhaps someone else reading this will appreciate it. Electrons in orbitals are mostly standing waves. The waves have a wave function in 3d space, which has a value at every point in space. The wave function value can be + or - (this is not electric charge). When two atoms have orbital wave functions that overlap, they interact. If both of them are + (or both -) they reinforce each other, form a lower energy state and form a bond. If 1 is + and the other -, they will repel each other, it's an "antibond". If there are two electrons in an orbital they will have the same wave function but of opposite sign. They will cancel so the electrons don't participate in bonds with other atoms. In a p orbital the wave function looks like a 3d figure 8. One lobe of the 8 is +, the other -. In benzene, if the plane of the carbons is horizontal, there is 1 "8" per carbon atom standing upright, each with 1 electron, with the carbon nucleus at the "waist" of the 8. All the "+" lobes are on the top and all the "-" lobes the bottom. All the "+" lobes interact with each other and form a big bond. They mostly interact with their 2 immediate neighbors but to a certain extent each interacts with all 5 others. The same thing happens with all the "-" lobes on the other side of the plane of carbons. The merged "8" lobes form two "clouds" of electrons, one on each side of the plane of the carbons. How other atoms interact with these clouds of p electrons defines the chemistry of benzene and other ringed compounds.