RESIDUE   MAC      8
CONECT      HG     1 O1  
CONECT      C1     3 O1   O2   C2  
CONECT      O1     2 HG   C1  
CONECT      O2     1 C1  
CONECT      C2     4 C1   H21  H22  H23 
CONECT      H21    1 C2  
CONECT      H22    1 C2  
CONECT      H23    1 C2  
END   
HET    MAC              8
HETNAM     MAC MERCURY ACETATE ION
FORMUL      MAC    C2 H3 Hg O2