Ethanium: Difference between revisions
Ethynium should be C2H3+ |
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Like its "unsaturated" relatives ethenium and [[ethynium]] {{chem|C|2|H|3|+}}, the ethanium ion was conjectured to have (at least momentarily) a proton bound simultaneously to the two [[carbon]] atoms, and the electrical charge evenly spread between them, as in other [[non-classical ion]]s. The alternative "classical" structure would have the charge and the extra hydrogen bound to only one of the two atoms, i.e. a [[methyl group|methyl]]ated [[methanium]] ion. |
Like its "unsaturated" relatives ethenium and [[ethynium]] {{chem|C|2|H|3|+}}, the ethanium ion was conjectured to have (at least momentarily) a proton bound simultaneously to the two [[carbon]] atoms, and the electrical charge evenly spread between them, as in other [[non-classical ion]]s. The alternative "classical" structure would have the charge and the extra hydrogen bound to only one of the two atoms, i.e. a [[methyl group|methyl]]ated [[methanium]] ion. |
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Earlier calculations had predicted that the energies of the two forms should be 4 to 12 [[kilocalorie|kcal]]/[[mole|mol]] lower than the dissociated state {{chem|C|2|H|5|+}} + {{chem|H|2}}, and they should be separated by a slightly positive energy barrier.<ref name=yeh/> |
Earlier calculations had predicted that the energies of the two forms should be 4 to 12 [[kilocalorie|kcal]]/[[mole|mol]] lower than the dissociated state {{chem|C|2|H|5|+}} + {{chem|H|2}}, and they should be separated by a slightly positive energy barrier.<ref name=yeh/> Gas-phase [[infrared spectroscopy]] has shown that both forms are stable.<ref name=yeh/> The bridged structure has the lowest [[energy]], 4 to 8 [[kilocalorie|kcal]]/[[mole|mol]] lower than the classical one.<ref name=yeh/> |
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==References== |
==References== |
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Revision as of 00:27, 16 February 2013
In chemistry, ethanium or protonated ethane is a positive ion with formula C
2H+
7. It can be described as a molecule of ethane (C
2H
76) with one extra hydrogen atom and a +1 electric charge.
Ethanium is one of the simplest carbonium ions (after methanium CH+
5). It was first detected in 1960 by S. Wexler and N. Jesse in the ions produced by electrical discharges in rarefied methane or ethane gas.[1] It easily dissociates into ethenium C
2H+
5 and molecular hydrogen H
2.
Structure
Like its "unsaturated" relatives ethenium and ethynium C
2H+
3, the ethanium ion was conjectured to have (at least momentarily) a proton bound simultaneously to the two carbon atoms, and the electrical charge evenly spread between them, as in other non-classical ions. The alternative "classical" structure would have the charge and the extra hydrogen bound to only one of the two atoms, i.e. a methylated methanium ion.
Earlier calculations had predicted that the energies of the two forms should be 4 to 12 kcal/mol lower than the dissociated state C
2H+
5 + H
2, and they should be separated by a slightly positive energy barrier.[1] Gas-phase infrared spectroscopy has shown that both forms are stable.[1] The bridged structure has the lowest energy, 4 to 8 kcal/mol lower than the classical one.[1]