Contributing structures are not isomers of the target molecule or ion since they only differ by the position of delocalized electrons. Also Known As mesomerism. Actively scan device characteristics for identification. Use precise geolocation data. Select personalised content. Create a personalised content profile. Measure ad performance.
Select basic ads. Create a personalised ads profile. Key Points Lewis dot diagrams are often employed to visualize the covalent bonding between atoms in a compound. However, when multiple equally valid structures can be drawn, these structures are called resonance structures. Resonance structures have the same number of electrons and therefore have the same overall charge.
Resonance structures differ only in the arrangement of electrons; the atoms keep the same connectivity and arrangement. Show Sources Boundless vets and curates high-quality, openly licensed content from around the Internet. Licenses and Attributions. CC licensed content, Shared previously. Reference Terms. Lewis dot diagrams often cannot represent the true electronic structure of a molecule. Resonance structures are then employed to approximate the true electronic structure. Related Stories.
In the This research may have applications in improving the At this point, both terminal oxygen atoms have octets of electrons.
We therefore place the last 2 electrons on the central atom:. The central oxygen has only 6 electrons. We must convert one lone pair on a terminal oxygen atom to a bonding pair of electrons—but which one? Depending on which one we choose, we obtain either. Which is correct? In fact, neither is correct. As you will learn, if the bonds were of different types one single and one double, for example , they would have different lengths. It turns out, however, that both O—O bond distances are identical, Equivalent Lewis dot structures, such as those of ozone, are called resonance structures.
The position of the atoms is the same in the various resonance structures of a compound, but the position of the electrons is different. Double-headed arrows link the different resonance structures of a compound:. The double-headed arrow indicates that the actual electronic structure is an average of those shown, not that the molecule oscillates between the two structures.
When it is possible to write more than one equivalent resonance structure for a molecule or ion, the actual structure is the average of the resonance structures. Like ozone, the electronic structure of the carbonate ion cannot be described by a single Lewis electron structure.
Because carbon is the least electronegative element, we place it in the central position:.
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