Questions tagged [lewis-structure]

For questions about determining Lewis structures (or their validity) for different chemical species. Do not use this tag if your question is about determining [oxidation-state] or [formal-charges], use the other respective tags instead.

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21
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2answers
5k views

Which relatively simple molecules violate the octet rule?

I'm learning how to draw Lewis diagrams. Everything I've read emphasizes the octet rule. However, to the best of my knowledge, that rule only applies to elements in the first three periods. On our ...
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5answers
75k views

The Lewis structure of HNO3

So I was checking the structure of nitric acid in Wikipedia, however I couldn't quite fathom why it looked like that because it seemed to contradict the following statement: A Lewis structure with ...
15
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1answer
4k views

Lewis Structure on (CH3)2NO?

I've been taking an chemistry class online (for fun only) and one of the questions in the homework threw me a bit. Here's the wording: "Draw the Lewis structure for a nitrogen atom attached to. two ...
14
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5answers
11k views

Structure of NO2 compound?

What is the correct structure for the $\ce{NO2}$ compound (not ion)? I always thought it was like: since the negative charge would be residing the on the highly electronegative oxygen, but was ...
14
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1answer
5k views

Order of dipole moments

What is the order of dipole moments for $\ce{SO3, SiO2, P2O5,}$ and $\ce{Cl2O7}$? This question is from a book and the answer given is $\ce{Cl2O7 < SO3 < P2O5 < SiO2}$. Can someone explain ...
11
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4answers
1k views

Does benzene structure stand for a single resonance form or the whole molecule?

It is known that benzene has two main resonance forms Often we still draw benzene molecule as one of them My question is, actually when we draw the lower figure, do we refer to the whole benzene ...
11
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2answers
593 views

Misleading features of Lewis Dot Representation

Today I had an embarrassing experience when I sat to help my nephew learn Lewis' Dot Representation and realized that I actually don't get it at all. I have a physics background and always thought ...
11
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2answers
27k views

Why are least electronegative elements usually in center of lewis structure

Many sources state that one of the primary rules for molecular structures is that the least electronegative element is in the center. However, none of them explain why this is the case. Is this ...
10
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6answers
25k views

What is the Lewis structure for HClO?

In many sites, I see that they put $\ce{O}$ in the middle, but our teacher said that we should put $\ce{O}$ near the extremity. Which is the best way?
10
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1answer
4k views

What allows sulfur and phosphorus to expand their octet?

There are many compounds in which the stability of a molecule is not governed by the presence of octet configuration in central atom. In most of the cases the central atom is generally sulfur or ...
10
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2answers
9k views

Ozone resonance structure: differing opinions

I've always thought that the two-form resonance structure of ozone was the scientific concensus (from Wikipedia]: Then today I found two other opinions. A three-form structure: And a four-form ...
10
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2answers
655 views

What is the structural formula of alkali hypohalite: MOX or MXO?

Recently I came across this question and in the comment section, there was an argument regarding the formula of sodium hypoiodite which kept me wandering: what is the actual formula of alkali ...
9
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1answer
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What is the Lewis Structure for CO?

In many sites I see that they take $\ce{C}$ with valence 4, bur our teacher takes it with valence 2. With what valence should I take $\ce{C}$?
9
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2answers
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What is the correct structure of sodium thiosulfate?

Which structure of sodium thiosulfate is correct? One book says the second one (the one with co-ordinate bonds) and the other one says the first one? According to me the structure 2 is correct as in ...
8
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4answers
4k views

Why does stannous chloride occur despite the octet rule?

Shouldn't reaching an octet be any atom's "goal"? However, I've recently learned about cases that are either expanding octets, or have lesser than "enough" electrons for an octet abiding. e.g.: S in ...
8
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1answer
2k views

Full Valence Shell (Octet Rule) vs Formal Charge

When does formal charge have more precedence over the octet rule / an atom having a full valence shell when drawing structures? When you draw $\ce{BCl3}$ for example, there are no double bonds - ...
7
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2answers
7k views

What is the molecular geometry of NHF₂?

I had to draw the molecular shape for $\ce{NHF2}$ as a Trigonal Planar like this But when I check to make sure it was right, I came across a source saying NHF2-difluoroammonia--tetrahedral, ...
7
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3answers
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π Bonding in Carbon Dioxide

I am fairly sure the first diagram I drew for carbon dioxide is wrong in terms of showing π bonding. This is because we use a π orbital twice, which isn't possible. The second diagram corrects this by ...
7
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2answers
12k views

Why is O2 a biradical?

$\ce{O2}$ has a double bond in its normal form. That is $\ce{O=O}$. There are no unpaired electrons in this case are there since there are 2 lone pairs on each oxygen. However 1 resonance structure ...
7
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3answers
3k views

Why is there a need for resonance?

Why are we able to show structures of compounds with different position of electron, but with same position of them? Shouldn't the structure become unstable due to this? Let's take benzene for the ...
7
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2answers
8k views

Is this a valid structure for the nitrate ion?

Why is the below structure not considered a valid structure for the nitrate ion? Is it because adding a double bond reduces the formal charges present on the nitrogen? Does the above form exist ...
6
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6answers
24k views

What is the proper Lewis structure for HCOOH?

I tried to draw the Lewis structure of $\ce{HCOOH}$ but I didn't get the correct representation. As you can see in the picture below, at no. 1, I put $\ce{C}$ as the central atom because it has less ...
6
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1answer
9k views

What is the correct Lewis structure of NH3O?

Choose the most appropriate Lewis structure for $\ce{NH3O}$ among the two: and The oxygen in the second case has 3 nonbonding pairs around it. I chose the first as an answer, yet the second ...
6
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2answers
1k views

Lewis Structure of OF+

Would the Lewis Structure for OF+ be drawn so that the more electronegative atom has the more negative formal charge, or would it be drawn to satisfy the octet rule? Here are my thoughts thus far: ...
6
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1answer
19k views

Structures for NO+ (Nitrosonium)

There are two possible structures for Nitrosonium : In the first structure, there is a +1 Formal charge on Oxygen, whereas, In the second structure, there is a +1 Formal charge on Nitrogen. Q. ...
6
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1answer
1k views

Lewis structure for NCO+

I proposed the following lewis structure for $\rm NCO^\oplus$ The problem is that this structure is linear, while my book tells that the structure is not linear. What will be correct canonical ...
6
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1answer
309 views

Lewis structure for magnesium diboride

What is the Lewis structure for $\ce{MgB2}$? I just read that it is a superconducting material (up to a relatively high critical temperature, 39 K) and am wondering if this has to do with its ...
6
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1answer
3k views

Limitations of Lewis structures

Using Lewis structures to describe chemical bonds inside a molecule is still fairly common start in undergraduate education. Lewis structure however can be misleading, or just simply wrong in many ...
5
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2answers
860 views

What is the correct lewis structure of SCH⁻?

I need to find the Lewis structure of the ion $\ce{SCH^-}$. I think the Lewis structure should be: $\ce{S=C-H}$, with one lone pair on the carbon and two lone pairs surrounding the sulfur. Is this ...
5
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2answers
726 views

Can linear SOCl2 exist?

Specifically, instead of its normal structure, this Lewis structure seems to be valid as a constitutional isomer: $\ce{Cl-O-S-Cl}$ So what prevents this from existing, or if it already exists how is ...
5
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1answer
850 views

Where do the lone pairs go in the “true” resonance structure?

Consider the "true" resonance structure of $\ce{CO3^2-}$: The bottom diagram leaves out the 2 lone pairs, so 4 electrons disappeared in the bottom image as compared to the top one. Are these ...
5
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2answers
10k views

Lewis structure of Cl2SO

Why is it that the Lewis structure of $\ce{Cl_2SO}$ has a total of $24$ valence electrons? I thought that the number of valence electrons should be $2\times7 + 1\times6 + 1\times6 = 26$.
5
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3answers
2k views

The definition of formal Charge

Ok, most people including me know that formal charge is just a book-keeping tool. I know how to calculate it, apply it to Lewis structures etc etc. But I am confused in its very basic definition which ...
5
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2answers
45k views

How is the Nitrate Ion (NO3) formed?

I understand how the nitrite $\ce{NO2}$ ion can be formed and have a negative charge, but the nitrate $\ce{NO3}$ ion is confusing me. I made some simple drawings to try to explain what I don't ...
5
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3answers
555 views

How to identify the most stable Lewis adduct of boron trichloride?

Which of the following is the most stable Lewis acid–base adduct? (a) $\ce{H2O\bond{->}BCl3}$ (b) $\ce{H2S\bond{->}BCl3}$ (c) $\ce{H3N\bond{->}BCl3}$ (d) $\ce{H3P\bond{->}BCl3}$ ...
5
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1answer
2k views

Why does H bond to S in HSO3?

In the structure of $\ce{HSO3-}$, we see that the H is bonded directly to the S, not to the O's, as would be the case in other oxyacids. Why is this the case?
4
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4answers
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Structure of pyrophosphorous acid

What is the structure of pyrophosphorous acid? I asked this question here because the answer which I found on web and other resources are inconsistent which each other. For example, following data is ...
4
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2answers
4k views

Is SbF5 symmetrical?

SbF5 forms a trigonal bipyramidal shape. There are polar bonds present and I assumed that it is non polar because of it's molecular geometry. However, The molecule itself is not entirely symmetrical (...
4
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1answer
43k views

The Lewis structure for NCO-

I was having trouble drawing the Lewis structure for $\ce{NCO^-}$. I found this image online: But why is structure number one preferred over structure number two? Why does carbon prefer to have a ...
4
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1answer
1k views

Why is this a Lewis structure of ethyl acetate?

I read somewhere that the structure in the following picture is a Lewis structure of ethyl acetate. However, I don't understand why: The $\ce{C}$ has a positive charge, but only three bonds The $\...
4
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1answer
7k views

What is the correct Lewis structure for calcium phosphate?

In calcium phosphate, $\ce{Ca3(PO4)2}$, since the calcium and phosphate share an ionic bond, and the phosphorus and oxygen share a covalent bond, should the Lewis structure be like the following? ...
4
votes
1answer
13k views

What is the correct Lewis structure of diazomethane?

I tried to google and watch YouTube videos on how to write Lewis structures properly, but I can't seem to understand how to do this correctly. My teacher, when class was in session, gave me a set of ...
4
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2answers
6k views

Why is Graphene So Strong?

There has been a lot of news about Graphene since its discovery in 2004. And as we are all told it is a revolutionary material which is very strong, conductive and transparent; even in some cases it ...
4
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2answers
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Why do unbonded electrons exist in pairs?

Basically the term which we use to refer them is lone pair. In Lewis structure why we represent those unbonded electron in pairs. Like here (structure of SO2) Here if we assume both the unbonded ...
4
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1answer
3k views

Why is the Chlorine missing an electron in Chlorine Monoxide?

I was asked to draw the lewis-dot structure for ClO and I drew this: .. .. :Cl- O. .. .. The correct answer is apparently this: ...
4
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1answer
1k views

Formal charges on polyatomic ions

Why is it that sometimes a polyatomic ion's Lewis structure is adjusted to remove the formal charge on the central ion, but sometimes it is not? For example, in the $\ce{I3-}$ ion (triiodide), the ...
4
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2answers
995 views

Why does O2NCl only have two resonance structures?

Why is it that $\ce{O2NCl}$ has only two resonance structures? More specifically, why is the Lewis drawing where $\ce{N}$ is double bonded to $\ce{Cl}$ not considered a resonance structure along with ...
4
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1answer
1k views

Do atoms react to fill outer shell or 8 valence electrons? [duplicate]

I recall in middleshool chemistry we simply said electron shell configurations were 2,8,8,many which I would have no problems with. But now I'm learning that shells contain $2n^2$ electrons where n ...
4
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0answers
518 views

What is an algorithm for drawing resonance structures?

Question What is an instance of a procedure for writing resonance structures for any given compound's name or structural formula? I would prefer any of these formats to represent the algorithm: ...
4
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3answers
18k views

Identifying coordinate bonds

How can we know whether a compound has a coordinate bond or not? I know that I have to draw the Lewis Structure for the compound. But what to do after that? Is there anything to do with formal charges?...