Step 1: Understand what isomerism is. Isomerism is when two or more compounds have the same formula but different structures or properties.
Step 2: Identify the complex in the question, which is [Cr(en)3]3+. Here, 'Cr' is chromium and 'en' stands for ethylenediamine.
Step 3: Recognize that ethylenediamine (en) is a bidentate ligand, meaning it can attach to the metal (Cr) at two points.
Step 4: Determine the geometry of the complex. [Cr(en)3]3+ has an octahedral shape because it has six coordination sites filled by three bidentate ligands.
Step 5: Check for chirality. A molecule is chiral if it cannot be superimposed on its mirror image. The arrangement of the three en ligands around the chromium creates a non-superimposable mirror image.
Step 6: Conclude that since [Cr(en)3]3+ has chiral centers due to the arrangement of the bidentate ligands, it exhibits optical isomerism.
