butene
  -ISIS-            2D

  4  3  0  0  0  0  0  0  0  0  1 V2000
   17.9805    0.0000    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0
   16.5581    0.0000    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0
   15.2325    0.0000    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0
   13.8035    0.0000    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0
  1  2  1  0  0  0  0
  2  3  2  0  0  0  0
  3  4  1  0  0  0  0
M  END