Abstract
Analysis of the proton and 13C-H satellite N.M.R. spectra of pyridazine has given the following H-H coupling constants: J 34 = 5·05 c.p.s., J 35 = 1·85 c.p.s., J 45 = 8·00 c.p.s., J 36 = ± 1·40 c.p.s.; the 13C-H couplings are 183 c.p.s. and 168 c.p.s. respectively for the 3 (or 6) and 4 (or 5) positions.