The Structure of Cyclic C₆S₆ and C₆O₆

The energetically most favorable isomer of C₆S₆ detected in the gas phase is not aromatic but quinoid. The difference in energy between A and B was determined by ab initio calculations to be 10.9 kcal mol⁻¹. In contrast, the hexathioketone C, which should have a chair conformation, has an energy almost equal to that of B. (Figure Presented.)