CNO- Lewis Structure: How to Draw the Dot Structure for the CNO- (Cyanate Ion)

A step-by-step explanation of how to draw the CNO- Lewis Dot Structure (Cyanate ion).

For the CNO- structure use the periodic table to find the total number of valence electrons for the CNO- molecule. Once we know how many valence electrons there are in CNO- we can distribute them around the central atom with the goal of filling the outer shells of each atom.

In the Lewis structure of CNO- structure there are a total of 16 valence electrons. CNO- is also called Cyanate ion.

Also note that you should put the CNO- Lewis structure in brackets with as 1- on the outside to show that it is an ion with a negative one charge.

----- Steps to Write Lewis Structure for compounds like CNO- -----
1. Find the total valence electrons for the CNO- molecule.
2. Put the least electronegative atom in the center. Note: Hydrogen (H) always goes outside.
3. Put two electrons between atoms to form a chemical bond.
4. Complete octets on outside atoms.
5. If central atom does not have an octet, move electrons from outer atoms to form double or triple bonds.

----- Lewis Resources -----

Lewis Structures, also called Electron Dot Structures, are important to learn because they help us understand how atoms and electrons are arranged in a molecule, such as Cyanate ion. This can help us determine the molecular geometry, how the molecule might react with other molecules, and some of the physical properties of the molecule (like boiling point and surface tension).

[KsstheStrs]

Thank you so much for this video! I couldn't figure out why it wasn't appropriate to have a double bond with Carbon and Nitrogen. Quick and informative! Once again, thank you! :)

[wbreslyn]

Hey CamtheShammy. You are right.

I annotated the video stating that this is the cyanate ion Lewis structure. I then did a new video for fulminate (with the nitrogen in the center as you suggested) and linked to it from this video.

Thank you for spotting my error.

Humbly,

Dr. B

[wbreslyn]

Actually I now see what everyone is saying in the comments. Yes, it is the cyanate ion. I annotated the video to say "Cyanate Ion" and then made a video for the Fulminate ion (and linked to it from this video).

Thanks for catching my error - that is an important distinction.

Dr. B

[wbreslyn]

So the equation I prefer is:
Formal Charge = Valence Electrons (based on the Group they are in on the Periodic Table) - NonBonding Valence Electrons - Bonding Valence Electrons/2

FC = V - N - B/2

N = 5 - 2 - 6/2 = 0
O = 6 - 6 - 2/2 = -1

Does that make sense?

[Cambeast]

Is this the only way you can write the single best Lewis Structure? I took an exam where I had to do this, but I included double bonds instead of a single and a triple (professor never mentioned electronegativity when teaching us how to draw Lewis Structures). I understand now why I got no credit, but does that mean the double bond is not possible for cyanate? Can a cyanate ion still form with a double bond?

[huntersikari]

Hello Dr. B
For the fact that carbon made 3 bonds with nitrogen and 1 with oxygen and not the other around or any other way and it was also convenient to see Oxygen carrying -1 charge and also the CNO- has -1 charge. Is this concept solely the right way to figure that out . I was just curious since you mentioned "it makes sense". Does it makes sense most of the time?

Thanks for the videos

[CamtheShammy]

Since this is fulminate, shouldn't the nitrogen be the central atom?

[loicthekin]

formal charge of N is 4-3-2= -1 and N 5-4 = +1? Or am I wrong?

[cottoncandy]

Can I do the opposite? To make between O and C a triple bond?

[wbreslyn]

Yep. It's usually written as [OCN]− or [NCO]− but the Lewis structure is the same.

[livia]

Why isn't there a +1 charge on N? 5-4=1.

[madhulikamalhotra]

can you please tell me what would be it's hybridisation...

[TridTV]

would it make any difference if it was CNO^-

[semir]

Isn't that lewis structure of the cyanate ion?

[lucasfreitas]

A N=C=O structure also has two zero formal charges and a -1 formal charge, but in Nitrogen instead.

The fact that actually makes N–C三O the best Lewis structure is that the negative formal charge is in the MOST ELECTRONEGATIVE atom (O), rather than N or C.

In other ionic tie cases like that, check if the excess or lack of formal charge is in the most or least electronegative atom, respectively.

[alex.gmez]

Why are there 16 valence electrons? Oxygen has 6, Nitrogen has 5, and Carbon has 4. Because of the negative charge?