Electrolysis omission - Journal of Chemical Education (ACS

Electrolysis omission. Kenneth E. Kolb, and Doris Kolb. J. Chem. Educ. , 1987, 64 (1), p 92. DOI: 10.1021/ed064p92.3. Publication Date: January 1987...
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Speclflc-Documented Assertion of the Term "Carbonlum" as Correct and the Term "Carbocatlon" as Incorrect To the Editor;

I t is the purpose of this letter to assert that the term "carbocation" has been incorrectly and inconsistently replacing the term "carbonium ion" in some quarters, by defining the basis for the use of thesuffix "-onium" as applying to species containing more bonds than usual, as well as a ~ o s i t i u echaree at the atom in ouestion . . . asammonium. oxonium, sulfonium, and phosphonium . . . so that consistency-with-definition demands a "carbonium" species to he the likes of the mass spectrometrically detected CH&+(pentavalent). Hence, accordina to this definition. the likes of the species CR3+,though posit&ely charged a t the atom in question, is stated to possess less bonds than its usual four . . . and therefore must he given a term other than "carhonium" . . .and is consequently dubbed "carbocation". The followiue enumerates a snecific-documented asnertion that the original term "carhonium" is actually correct, while the recently introduced term "carhocation" is incorrect in its definition, inconsistent in its application, and unnecessary to invoke as a new classification term. (1 I The species, CR1'. is universally asserted rn be ~ p and ' hence possesrrs its uruol rhree groups.. . not lese bonds. as stated in the a h o w definition. Therefwe, the ahwe definition is based on an incorrect premise. (2) The mass spectrometrically detected CHs+ cannot he sp3hypervalent, hut its orbital hybridization could represent another oxidation state of carbon .. . just as there is normally trivalent "nitrous" and normally pentavalent "nitric". (3) The same texts, that replace the term "carbonium ion" with the term "carbocation" are calling the hypovalent,+ NOz, "nitronium," instead of "nitrocation", and the hypovalent,+ CI,+ Br, etc., "haloniurn" instead of "halocation" or no term, whatsover) .. . in the familiar electrophilic aromatic substitution .. . in embarrassing inconsistency with their crusade to revise and upgrade the nomeudature. (4) H2S04,sulfuric acid, is ostensibly hexavalent sulfur, as is its dehydration product, S03,sulfurictrioxide.. .but only the latter,in fuming sulfuric acid, will sulfonate benzene . . . by virtue of the resonance polarization of a sulfur-to-oxygen bond, resulting in a hypovalency of sulfur. Using the "carbonium" terminology, this would be "sulfonium character"; hut using "carbocation" terminology, this would be "sulfocation" character. ..that enables the electroohilic aromatic sulfonation. The "earhoeation" adherents term thdorotonated sulfhvdrvl . . eroun " . to he a sulfonium. as do those texts using "carbonium" nomenclature . . . to the latters' inconsistency, except that sulfur trioxide is given no "named" cationic character of the sulfur.

Furthermore, the application of the term ''carbocation" has been based on incorrect premises, and the error compounded by inconsistency of leaving the noncarbon cations with their original "onium" nomenclature. M. Gerald Schwartz Salve Regina College Newpnt, RI 02840

m e Density of Solids To the Editor:

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Electrolysis Omlsslon To the Editoc

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In conclusion, the term, "carbocation" is a n unnecessary replacement for the term "carhonium", the latter serving sufficiently for all positively charged species, regardless of number of bonds to the atom in question.. . with the provision, however, that cations (or cationic character) of different oxidation states of the atoms in question would need to he distinguished by nomenclature . . . as "enium", "inium", and "onium", for example.

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The experiment described in this Journal [1984,61,242] by Dale Burgess augmented with the "Density of Liquids" and entitled "Density Determination" is assigned to those in general chemistry at my school. - An irregular shapedobject, a regular shaped object, and two liquids are given for the required determinations. The irregular shaped object is weighed and then immersed in a liquid whose density is less than than of the selected object and will not act as a solvent on the obiect. The volume of the chosen liquid is recorded before and after immersion. The density of the object is the weight divided by the volume difference. The regular shaped object (a sphere, a cylinder, a cube, or a block) is weighed then measured with either a centimeter ruler or a micrometer caliper. The volume of the sphere, the cylinder, the cube, or the box are calculated by V = 4ar3/3, V = *r2h, V = P, and V = lwh after the dimensions are measured, and these volumes are divided into the respective weights to obtain the density. Suitable-size, calibrated beakers are weighed when empty and a specified volume of the chosen liquids are poured into the beakers and weighed again. The weight difference in each case divided by the specified volume is the denisty for the selected liquids. After completion a signed written report from each student is required by a specific deadline. The written format for all assigned experiments is (1)Name of Experiment, (2) Purpose, (3) Apparatus (Materials), ( 4 ) Description, ( 5 ) Data, (6)Calculations, and (7) Results and Conclusions. William D. Hill Jr. North Carolina Central University

Journal of Chemical Education

In a recent note we described a simple, compact electrolysis assembly for overhead projector demonstrations using two pencils as electrodes. We mentioned that we had seen Henry Bent use pencils as electrodes, but we failed to acknowledge Walter Selig's article [J. Chem. Educ. 1984, 61, 801 that describes electrodes made from pencils. We regret this oversight. Kenneth E. Kolb and Doris K. Kolb Bradley University Peoria. IL 61625

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I. Pfluger, R. W.; Lyster, M. A.; Lowe, J. A., 111. J . Org. Chem. 1982,

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47.1160-1 166.~ ~

2. Blake, P.; Henri-Rousseau, 0.;Merad, M. J. Chem. Educ. 1984, 61,957-961.

Note that all parts of the author's name except the last name Volume 64 Number 1 January 1987

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should he in the form of initials only. All authors' names should he eiven: do not use "et al." in the references ihowever, it is acceptable in the text). The name of the jourha~is underlined (includine J. Chem. Educ.): this is followed hv the year, volume (in Lrabic, not ~oman,'numerals),and firdt and last page numbers. Reference to journals that renumber their pages with each issue should contain the issue number in parentheses after the volume number. 3. Nassau, K. Sci Am. 1980,243 (4), 124.

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Books Reference to a whole book 4. Holmes, B. E.; Setzer, D. W. Physical Chemistry of Fast Reoc-

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Reference to a contribution in a book edited by other(s) 6. Pollard, R. T. fn Comprehensive Chemical Kinetics, 4th ed.; Bramford, C. H.; Tipper, C. F. H., Eds.; Elsevier: New York,

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Material accepted for publication but not yet published 9. Stankovich, M.; Fox, B. Biochim. Biophys. Acta, in press. Unpublished results 10. Wulff, W. D.; Chan, K. S.; Tang, P. C., unpublished results

Theses 11. Fisher, W. G. PhD Thesis, Cornell University, 1978.

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personal communication, 1962.

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Journal of Chemical Education

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