\vbox{
\centerline{\structure{\nopositioncheck
\atom{O}\etriple\atom{C}\esingle\firstbicycloatom{Fe}
\side{\nwsingle\atom{C}\nwtriple\atom{O}}
\side{\swsingle\atom{C}\swtriple\atom{O}}
\sesingle\atom{C}\side{\sdouble\atom{O}}\nesingle\phantatom{Fe}
\side{\esingle\atom{C}\etriple\atom{O}}
\side{\sesingle\atom{C}\setriple\atom{O}}
\side{\nesingle\atom{C}\netriple\atom{O}}
\nnwsingle\secondbicycloatom{C}\side{\nnedouble\atom{O}}
\ssephantom\firstbicycloatom{Fe}\swphantom\phantatom{C}
\nwphantom\phantatom{Fe}\nnesingle\secondbicycloatom{C}
\side{\nnwdouble\atom{O}}\sswphantom\firstbicycloatom{Fe}
\sephantom\phantatom{C}\nephantom\secondbicycloatom{Fe}}}
\medskip \centerline{\bf Figure~8. \rm 
Tri-$\mu$-carbonyl-bis(tricarbonyliron).}
}