text: One-bond coupling is illustrated by PH where J(P,H) is 189 Hz. Two-bond couplings, e.g. PCH are an order of magnitude smaller. The situation for phosphorus-carbon couplings are more complicated since the two-bond couplings are often larger than one-bond couplings.  The J(C,P) values for triphenylphosphine are respectively −12.5, 19.6, 6.8, and 0.3 for one-, two-, three-, and four-bond couplings.