1,2-Diiodoethylene, also known as 1,2-diiodoethene, is an organoiodide with the molecular formula C2H2I2.

It can exist as either of two geometric isomers, cis-1,2-diiodoethylene or trans-1,2-diiodoethylene.

Like most cis-trans compounds, the Z isomer (cis) is less stable than the E isomer (trans) by 2 kcal/mol.

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