TMS Flashcards
What does TMS have?
12 H all in same environment with no polarity
What is the chemical shift of TMS?
0
Draw TMS
Si with 4 methyl groups around it
Why does TMS give a single strong peak?
All protons are shielded exactly the same amount
Why is TMS used as a reference point?
1) Volatile - evaporates off leaving pure sample
2) Doesn’t interact with sample molecules - doesn’t modify environment so doesn’t affect chemical shift
3) Most organic compounds have chemical shifts that are positive compared to TMS
Why are atoms of H magnetic?
They have nuclear spin so are able to absorb radio waves. H atoms in different environments absorb different frequency radio waves. Wavelength reveals environment of H