13C

• WHICH ISOTOPE OF CARBON HAS NUCLEAR SPIN?

  13C

  -> 12C does not
• WHAT IS DIFFERENT ABOUT ALL 13C ATOMS?

  resonate at different magnetic field strengths

  • feel magnetic field differently
  • all nuclei shielded from external magnetic fields
  • by electrons surrounding them
  • more electrons = more shielded
• WHAT CAUSES A LOWER FREQUENCY OF RESONATION?

  • greater electron density
  • smaller magnetic field felt by nucleus
  • lower frequency at which it resonates
  • smaller chemical shift value