P-QUINODIMETHANE AND ITS DIRADICAL. BY C. A. COULSON, D. P. CRAIG, ALLAN MACCOLL AND MDE. A. PULLMAN. Received 6th October, 1947. P-Quinodimethane (I) and its diradical (11) have been proposed by Szwarc as products in the pyrolysis of p-xylene : p-Quinodimethane. I. p-Quinodime thane di-radical. 11. In the followi