Illustrated Glossary of Organic Chemistry

Quartet: In NMR spectroscopy, a split signal composed of four lines, close together. The height of the lines will be close to 1:3:3:1 ratio.




Idealized quartet
Lines in a 1:3:3:1 ratio
  
"Leaning" quartet


The 1H-NMR spectrum of 2-ethylphenol has a quartet at 2.5 ppm due to the CH2 group. Click the image to see a larger version.