Spectroscopic techniques Flashcards
X-ray diffraction.
Electron density plot shows position of atoms. H atoms not detected due to minimal electron density around them.
Pros: Gives location of all atoms
Cons: Needs good quality crystals, H undetected
Mass spectrometry
Gives mass of sample molecules, plus information about bonding from fragments
Pros: Gives molecular formula, good for mixture analysis, tiny sample needed
Cons: Difficult to interpret when unknown
Mass spectrometry
Gives mass of sample molecules, plus information about bonding from fragments
Pros: Gives molecular formula, good for mixture analysis, tiny sample needed
Cons: Difficult to interpret when unknown
Electrospray ionisation steps
- Solution of sample sprayed through high potential nozzle
- Solvent evaporates leaving charged droplets
- Target molecule with ion attached is detected
IR Spectroscopy
Detects vibrational transitions in bonds. Only works when vibration leads to change in dipole moment.
Wavenumber equation
Raman spectroscopy
Used when there is no change in dipole moment