Question

Question #c4127

Answer 1

`HFC=CHF` and `F_2C=CH_2` are `"structural isomers."`

Explanation:

But `"cis-"HFC=CHF`, and `"trans-"HFC=CHF`, are `"geometric isomers"`. Why? Because the connectivity in each isomer is the same: `F_1` connects to `C_1`; which connects to `C_2`; which connects to `F_2`. Nevertheless, because their geometry is manifestly different, these are geometric isomers.

You will have to find a suitable picture, because my interwebs broke. See here for diagrams of cis and trans dichloroethylene.