The Lewis Dot Structure for CO2

Created by MakeTheBrainHappy
This is the Lewis Dot Structure for CO2. You could alternatively also draw the structure by including two dots for every bond. That would mean that you would have a total of eight dots around the carbon, thereby filling its octet. The octets of both of the oxygen atoms are also satisfied, since the oxygens have a total of eight electrons around them (thereby filling the valence shell). 

The lewis dot structure of CO2 gives it some unique properties. Since there are no lone pairs on the atom, it is a linear structure which makes the charges cancel it. Therefore it is nonpolar and relatively unreactive. These properties in addition to its small state makes it so that carbon dioxide has a low melting point and is mostly in the gaseous phase at STP (Standard Temperature and Pressure). Even though Carbon Dioxide is quite small, its density is still 1.67 times that of air.

A solid block of CO2. The IMF (intermolecular) forces holding this structure together are so weak that the cube is going directly from the solid to the gaseous phase. CO2 is solid at -78.5 ˚C. Source
Do other lewis dot structures for CO2 exist?

Yes, although these would not be the most common structures due to formal charges. You can learn more about what formal charge is in this article. An example of a possible resonance structure would be to make the double bonds in the lewis dot structure single bonds and then give the extra electrons to each of the oxygen atoms. This would give each oxygen atom a -1 formal charge and the carbon atom a +2 formal charge. While this would technically balance out, it would be unlikely due to the covalent nature of the bonds even though the bonds themselves are polar.

Does carbon usually form bonds like this?

Yes, carbon combined with another element usually creates nonpolar structures because carbon can form multiple bonds and rarely has lone pair electrons. It can easily fill its octet requirement with almost any combination of elements and its electronegativity allows it bond with many different types of atoms. The notable exceptions are the compounds CN (cyanide) and CO (carbon monoxide), which the bond is polar due to the unequal sharing of electrons between the two atoms in the structure. The structures do not look like the lewis dot structure for CO2, where the carbon does not have any lone pair electrons on the carbon.

The Lewis Structure for Carbon Monoxide with lone pair electrons on the carbon. Source
The Lewis Structure for Cyanide with lone pair electrons on the carbon. Source


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