# Stereo Isomerism - syn/anti

I was studying the types of stereo-isomerism E-Z, Cis-Trans and then I come across syn-anti stereo-isomerism this one is giving me a bit of fight in understanding, especially where lone pairs are taken into consideration.How do classify the molecules with lone pairs in consideration as syn and anti Please help me out here!

• @HydrousCaperilla Yes, cut the double bond perpendicular to the $\ce{C-N}$ axis, then figure out which group has the highest priority at the carbon, then do the same at the nitrogen and see if those two highest priority groups are on the same or opposite sides of the double bond.