[zeoblade]

I should have posted this a lot earlier because I have to give my answer very soon. I was wondering about how many resonances are expected in 13C NMR of n-butane and am thinking that the number of unique chemical environments dictates how many resonances there are. Looking at the structure, I don't know where the symmetry lies so I am inclined to say two: C1 + C4 and C2 + C3 but in the back of my mind, I feel there should be four resonances for each carbon. Can anyone clarify this for me?

[plankk]

Every peak in ¹³C NMR derives from diffrent carbon. So if you look at n-butane, you can see that C1 and C4 are the same, and also C2 and C3 are the same. "The same" means their electron enivorments are identical - they have the same neighbour. So we will see in the ¹³C spectrum only two peaks.

In the attachment the red line is a bisector of molecule.