COMPND  ethylene.pdb                                                            
HETATM    1  H                   0.910  -1.254   0.000                
HETATM    2  H                   0.910   1.254   0.000                
HETATM    3  C                   0.000  -0.661   0.000                
HETATM    4  C                   0.000   0.661   0.000                
HETATM    5  H                  -0.910  -1.254   0.000                
HETATM    6  H                  -0.910   1.254   0.000                
CONECT    1    3                                             
CONECT    2    4                                             
CONECT    3    1    4    5                                   
CONECT    4    2    3    6                                   
CONECT    5    3                                             
CONECT    6    4                                             
END