Bent molecules, carbon suboxide

Carbon suboxide C3O2 has been the subject of several papers. Earlier workers . disagreed as to whether the structure is linear or bent. A (9,5,I)->[4,3,1] basis set calculation concluded that it is essential to include f/-orbitals to determine the potential for CCC bending. Although the agreement with experiment was not satisfactory, the molecule is predicted to be non-linear but it was concluded that a more extensive basis set calculation is needed. Calculations including Cl are needed here. 

In the polymerization of carbon suboxide, the monomer molecules are incorporated into the polymer ladder as a part of a six-membered ring (Figure 1-b). Here both the electrophilic and the nucleophilic sites of the carbon suboxide molecule must participate in the reaction. In the initiation step, the first monomer is also required to assume a bent geometry, since two linear molecules colliding to form a six-membered ring is very unlikely due to the unfavorable spatial orientation. 

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