In NMR spectroscopy, difference between part 2 number of signal & splitting of signal #learnbasicss

Ajouté : 2026-05-22

[00:00:00]Hello everyone, this is a second short video on the NMR and in this today we discuss about the splitting of the signals, okay? So basically, let's start with the if the NMR nuclei shows the absorption whose value I whose I value greater than zero, okay? So basically, I take here uh isotopes and their spin quantum number, okay? So you can remember these values and that that is very helpful in the splitting.

[00:00:30]So basically, 12 carbon and 16 oxygen are non-magnetic nuclei because their I value will be zero. So you have to remember the formula first of all 2nI + 1 formula we are going to use for find the splitting or multiplicity. And this is not for the number of signals. You have to clear the difference between these two. So number of signals basically means how many different types of nuclei present. For example, we already discussed these two structures. Uh in F sub six, that is octahedral and getting the singlet. And in BrF3, we are already discussed about it. There is two types of fluorine present and therefore they give the two signal.

[00:01:15]And splitting we are going to find splitting of signals. We have to use this formula 2nI + 1 here. n is number of neighboring equivalent nuclei and I is spin quantum number. That is you can learn from here, okay?

[00:01:30]So basically, we take an example BrF3 and this is the structure. We have two fluorine, sorry, two fluorine axial position and one in equivalent. So basically, in splitting we see the influence of this equatorial fluorine with this and uh for this how these two fluorine in axial position affect this, okay? So for this we if we find and use this formula, we get the doublet. And for this one equatorial fluorine, we get the triplet by using this value, okay?

[00:02:04]And simply you have to put the value of n here. For one equatorial, you have two axial fluorine. So, basically n is two here, okay? And I value for fluorine is half, and simply put the value and you get the three answer, that is triplet.

[00:02:19]Similarly here, here n is one, and simply the this two will get cancelled this and simply doublet. So, basically this is the rule and you can find all the splitting pattern for all the molecules, okay? So, basically for I values half, we are not going to use this long formula 2nI + 1. We simply take this n + 1 because for half value of I, this two will cancel the this two and it will become n + 1, okay? So, you have to remember this for I is equals to half.

[00:02:53]So, that is the formula.

[00:02:55]So, that's all about today. Thank you.