BRAINCAKESpin-Spin Splitting
In a high resolution 1H NMR spectrum, many peaks are split into a group of closely spaced lines. This is called spin-spin splitting (or spin-spin coupling).
It happens because each hydrogen nucleus is a tiny magnet. Hydrogens on adjacent carbon atoms can each be aligned with or against the external field, which slightly increases or decreases the field felt by the hydrogen being observed. Each different arrangement of the neighbouring spins gives a slightly different resonance frequency, so the signal splits into several lines.
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Key terms in this lesson
- n+1 rule
- The rule that a hydrogen environment with n hydrogens on the adjacent carbon(s) is split into n + 1 lines in a high resolution 1H NMR spectrum.
More in Modern Analytical Techniques
- Retention Times
- Nuclear Magnetic Resonance
- Chemical Shift
- 13C NMR Spectroscopy
- 1H NMR Spectroscopy
- Integration Traces
- The n+1 Rule
- Deducing Structures from Combined Data
All 15 lessons in Modern Analytical Techniques · All Edexcel A-level Chemistry topics