1,2-Diiodoethylene

1,2-Diiodoethylene, also known as 1,2-diiodoethene, is an organoiodide with the molecular formula C$2$H$2$I$2$. It can exist as either of two geometric isomers, cis-1,2-diiodoethylene or trans-1,2-diiodoethylene.

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