GENERALLY TRANS ISOMERS ARE MORE STABLE THAN CIS ISOMERS BUT 1,2-difluoroethyleneCIS ARE MORE STABLE THAN TRANS ISOMERS...????EXPLIAN REASON PLEASE??

Cis 1,2-difluoroethylene is more stable than trans 1,2-difluoroethylene because the two highest singly occupied core orbitals have symmetry that allows them to make two two-electron multicentre bonds with two singly occupied fluorine type ligand MO’s which is not possible in trans isomer.