 However, he did not propose it as the structure of benzene, and in fact he supported the correct structure previously proposed by August Kekulé in 1865.Unlike benzene, Dewar benzene is not flat because the carbons where the rings join are bonded to four atoms rather than three.These carbons tend toward tetrahedral geometry, and the two cyclobutene rings make an angle where they are "cis"-fused to each other.