Double Bonds [ENDORSED]
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Double Bonds
How do you know which atom to double bond to? I know how to determine that a structure needs a double, but for example if it is NO3 how do we know which oxygen to double to? Does it matter?
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Re: Double Bonds
As long as you know which atoms need to be double-bonded, it does not matter! This is called resonance structure for a reason: where some lewis structures has multiple bonds in different equivalent locations.
Re: Double Bonds
In this case, any O can be double bonded to the central N, but in different cases, sometimes a double bond is preferred for certain elements in order to make the formal charge 0. For example, C usually has a formal charge of 0 when it has 4 bonds, but a different central atom can have lone pairs to make the formal charge 0. To add to this topic, sometimes even a triple bond is needed to minimize the formal charge.
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Re: Double Bonds
In this example it doesn't matter. If there are more than two types of elements in a molecule, just make sure you know which two specific elements should have the double bond between them.
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Re: Double Bonds
Hi, for NO3 it wouldn't matter. It has resonance structures because any of the oxygens could have the double bond
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Re: Double Bonds
In this case (and other cases where you have multiple of the same atom to which you can create a double bond to) it doesn't matter which one you form the double bond with. That is why we have resonance structures. Each of the resonance structures give us a limited view as to what the true structure of the molecule is: in these cases, electrons are often delocalized and therefore are shared in double bonds between the various atoms. Each resonance structure is simply an average of the true structure, therefore it doesn't matter which atom you form the double bond with. When there are various elements with which you could form the double bond with, then that will matter but at that point I believe it just comes down to electrons and octet rules.
Hope this helps!
Hope this helps!
Re: Double Bonds
Hi! When determining which element is going to produce the most stable bond, you can use the equation FC=V-(L+S/2) to calculate formal charge. Sometimes, moving the double bond around will result in different formal charges for at least one element. The goal is to make as most of these charges as close to zero as possible!
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Re: Double Bonds
In the case of NO3, you can choose which oxygen you want to have a double bond with, since the molecule displays resonance, which allows for multiple variations of the bond location in lewis structure drawing. However, in the case where you are not sure of where the double bond is, utilizing the most stable formal charges and trying to maintain the octet rule should help you figure out
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Re: Double Bonds
Hi! When determining where to put the double bond, you should check formal charge. If it is between one O atom and the N or another O atom and the N, then this is resonance and it does not matter where you put the bond, but if you have more options between different atoms then formal charge can help you determine where to place the double bond and form a more stable structure.
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Re: Double Bonds
It does not matter which atoms you double bond to. Because some compounds have resonance, as long as the double bond is there, it does not matter which O you double bond to :)
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Re: Double Bonds
Since it is a resonance structure, the double bond does not matter to which oxygen it goes to first.
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Re: Double Bonds
In the example you gave, it doesn't matter which O the double bond is at because they're all the same. However, if multiple elements could have a double bond, it's best to create a double bond where you'll get the formal charge of 0 because that's where it's most stable. You can find the formal charge using the equation FC=V-(L+S/2) where v is the number of valence electrons an element has, L is the lone electron pairs, and S is the shared electrons.
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Re: Double Bonds
Hello,
It should not matter which atoms have double bonds since some compounds have resonance.
It should not matter which atoms have double bonds since some compounds have resonance.
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Re: Double Bonds [ENDORSED]
Hi there! For this example, it doesn't matter cause it has resonance structures, which means that a double bond can occur in more than one possible location. When you're not sure where the double bond is, you can use the formal charge equation to determine where to place it; the goal is to form the most stable structure.
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Re: Double Bonds
In this example, it is a resonance structure so it does not matter which atom has the double bond.
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Re: Double Bonds
Adding on to what has been said above, resonance structures can be drawn with their double/triple bond wherever you want (as long as it is still between the same elements), but sometimes you may not have a resonance structure and a double bond is actually necessary in a certain spot. In these cases, you should just try to minimize the formal charge of each atom.
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