Cyclobutadiene Antiaromatic or Other Destabilization Factors?

Clearly cyclobutadiene is not aromatic. Is cyclobutadiene antiaromatic? Or is its lack of stability due to other factors? Cyclobutadiene is a four-carbon hydrocarbon. The –diene part of its name indicates it has two double bonds. The cyclo– part indicates it is not a chain structure, but a cyclic (ring) structure. Now double bonds hold atoms tighter than single ones do. So they are shorter than single bonds. This causes cyclobutadiene to assume a rectangular shape. If it were square instead, it would indicate the four carbon to carbon bonds were identical, and aromatic. Cyclobutadiene's four hydrogen atoms point away from the ring. Analyzing the Structure Cyclobutadiene is flat. The two double bonds of cyclobutadiene are conjugated. That is, their ring structure alternates double bond, single bond, double bond, single bond.…
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