Which of the following specific molecular setups will definitively FAIL to exhibit macroscopic Geome — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

Setup A is a 3-bond odd cumulene, which maintains co-planar ends and shows GI. Setup C is a square planar triphenyl system, which forces all three rings into the same plane, successfully showing GI. However, Setup B is a 2-bond even cumulene (allene), ending in perpendicular planes (no GI). Setup D is a heavily hindered biphenyl forced into orthogonal perpendicular planes to relieve steric strain, rendering cis/trans measurement impossible (no GI).