Coupling Constant or Spin-Spin Coupling Constant(J)
Coupling constant is the strength of the spin-spin splitting interaction and the distance between centers of two adjacent peaks or lines in a multiplet. It is also called spin-spin coupling constant (J).In the above diagram, one is quartered (A) and other is triplet (B). Quartered means three more protons are present in the neighboring proton and triplet means two more protons are present in the neighboring proton. Quartered or triplet are a multiplet in which more than one peaks are present so the coupling constant is the distance 'J' between the two adjacent peaks in a multiplet.
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