Benzen (Vietnamese Wikipedia)

Analysis of information sources in references of the Wikipedia article "Benzen" in Vietnamese language version.

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archive.org

bnf.fr

gallica.bnf.fr

books.google.com

doi.org

eco-usa.net

  • “Benzene trên www.eco-usa.net”. Bản gốc lưu trữ ngày 12 tháng 5 năm 2008. Truy cập ngày 15 tháng 6 năm 2008.

harvard.edu

ui.adsabs.harvard.edu

hathitrust.org

babel.hathitrust.org

jstor.org

nih.gov

pubmed.ncbi.nlm.nih.gov

  • Williams, P.R.D.; Knutsen, J.S.; Atkinson, C.; Madl, A.K.; Paustenbach, D.J. (2007). “Airborne Concentrations of Benzene Associated with the Historical Use of Some Formulations of Liquid Wrench”. Journal of Occupational and Environmental Hygiene. 4 (8): 547–561. doi:10.1080/15459620701446642. PMID 17558801.

uni-goettingen.de

gdz.sub.uni-goettingen.de

  • Claus, Adolph K.L. (1867) "Theoretische Betrachtungen und deren Anwendungen zur Systematik der organischen Chemie" (Theoretical considerations and their applications to the classification scheme of organic chemistry), Berichte über die Verhandlungen der Naturforschenden Gesellschaft zu Freiburg im Breisgau (Reports of the Proceedings of the Scientific Society of Freiburg in Breisgau), 4: 116-381. In the section Aromatischen Verbindungen (aromatic compounds), pp. 315-347, Claus presents Kekulé's hypothetical structure for benzene (p. 317), presents objections to it, presents an alternative geometry (p. 320), and concludes that his alternative is correct (p.326). See also figures on p. 354 or p. 379.

web.archive.org

  • “Benzene trên www.eco-usa.net”. Bản gốc lưu trữ ngày 12 tháng 5 năm 2008. Truy cập ngày 15 tháng 6 năm 2008.

wikipedia.org

de.wikipedia.org

  • Critics pointed out a problem with Kekulé's original (1865) structure for benzene: Whenever benzene underwent substitution at the ortho position, two distinguishable isomers should have resulted, depending on whether a double bond or a single bond existed between the carbon atoms to which the substituents were attached; however, no such isomers were observed. In 1872, Kekulé suggested that benzene had two complementary structures and that these forms rapidly interconverted, so that if there were a double bond between any pair of carbon atoms at one instant, that double bond would become a single bond at the next instant (and vice versa). To provide a mechanism for the conversion process, Kekulé proposed that the valency of an atom is determined by the frequency with which it collided with its neighbors in a molecule. As the carbon atoms in the benzene ring collided with each other, each carbon atom would collide twice with one neighbor during a given interval and then twice with its other neighbor during the next interval. Thus, a double bond would exist with one neighbor during the first interval and with the other neighbor during the next interval. Therefore, between the carbon atoms of benzene there were no fixed (i.e., constant) and distinct single or double bonds; instead, the bonds between the carbon atoms were identical. See pages 86–89 of Auguste Kekulé (1872) "Ueber einige Condensationsprodukte des Aldehyds" (On some condensation products of aldehydes), Liebig's Annalen der Chemie und Pharmacie, 162(1): 77–124, 309–320. From p. 89: "Das einfachste Mittel aller Stöße eines Kohlenstoffatoms ergiebt sich aus der Summe der Stöße der beiden ersten Zeiteinheiten, die sich dann periodisch wiederholen. ... man sieht daher, daß jedes Kohlenstoffatom mit den beiden anderen, ... daß diese Verschiedenheit nur eine scheinbare, aber keine wirkliche ist." (The simplest average of all the collisions of a carbon atom [in benzene] comes from the sum of the collisions during the first two units of time, which then periodically repeat. ... thus one sees that each carbon atom collides equally often with the two others against which it bumps, [and] thus stands in exactly the same relation with its two neighbors. The usual structural formula for benzene expresses, of course, only the collisions that occur during one unit of time, thus during one phase, and so one is led to the view [that] doubly substituted derivatives [of benzene] must be different at positions 1,2 and 1,6 [of the benzene ring]. If the idea [that was] just presented — or a similar one — can be regarded as correct, then [it] follows therefrom that this difference [between the bonds at positions 1,2 and 1,6] is only an apparent [one], not a real [one].)

worldcat.org

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