RESIDUE   GXT      6
CONECT      O1     1 C1  
CONECT      C1     3 O1   C    H1  
CONECT      C      3 C1   O    H2  
CONECT      O      1 C   
CONECT      H1     1 C1  
CONECT      H2     1 C   
END   
HET    GXT              6
HETNAM     GXT ethanedial
FORMUL      GXT    C2 H2 O2