BRAINCAKEThe TMS Standard
NMR chemical shifts are measured relative to a standard, tetramethylsilane, TMS, formula Si(CH3)4. Its signal is defined as δ = 0 ppm.
In TMS, four methyl groups are bonded to a central silicon atom, arranged tetrahedrally. All 4 carbon atoms are equivalent, and all 12 hydrogen atoms are equivalent.
TMS is chosen because:
Sign in free to see the rest of this lesson, the R.E.C.I.P.E. recall steps and the quiz
BrainCake is free. Make an account in seconds and pick up where this page stops.
More in NMR Spectroscopy
- Nuclear Magnetic Resonance
- Chemical Shift
- Deuterated Solvents
- 13C NMR Spectroscopy
- Interpreting 13C NMR Spectra
- 1H NMR Spectroscopy
- Relative Peak Areas
- Spin-Spin Splitting
All 12 lessons in NMR Spectroscopy · All OCR A-level Organic Chemistry topics