Reading 1H NMR Multiplets with Pascal's Triangle

1H NMR signal splitting helps identify how many neighboring protons a proton has. In an AX spin system, proton A senses the two spin states of a coupled proton X. That gives a doublet with two peaks of equal 1:1 intensity.

When proton A is coupled to two equivalent protons, the system becomes AX2...

Recall that a proton A can sense the two spin states of a coupled proton X, resulting in a doublet NMR signal with two peaks of equal intensity.

When A is coupled to two equivalent protons, their spin states can be aligned with or against the external field, creating three scenarios.

This results in a triplet signal, where the cent...