Bond Lengths and Angles Pi overlap brings carbon atoms closer. Bond angle with pi orbital increases. .Angle C:=C-His121.7°；Angle H-C-His116.6° Cis and trans isomers cannot be interconverted. No rotation around the carbon-carbon 1.33 16.6° ethylene ethane Bond Lengths and Angles ❖Pi overlap brings carbon atoms closer. ❖Bond angle with pi orbital increases. ◼Angle C=C-H is 121.7 ;Angle H-C-H is 116. 6 ❖Cis and trans isomers cannot be interconverted. ❖No rotation around the carbon—carbon