Pyrylium perchlorate

    Parameter     ppm  Hz

      D(A)         9.220
      D(B)         8.077
      D(C)         8.906
       J(A,A')         0.30
       J(A,B)          4.24
       J(A,B')         0.97
       J(A,C)          1.83
       J(A',B)         0.97
       J(A',B')        4.24
       J(A',C)         1.83
       J(B,B')         1.50
       J(B,C)          8.14
       J(B',C)         8.14
     
     RADICS,L. & KARDOS,J. ORG.MAGN.RESON. 5, 251 (1973)