Ethylene Plant hormone; polyethylene monomer 🧪 Building Blocks PDB source ↓ Drag to rotate · scroll to zoom 3D viewer requires JavaScript. Static renders available below. Structure Formula C2H4 Molecular weight 28.054 g/mol Heavy atoms 2 Total atoms 6 Composition C ×2 H ×4 SMILES C=C ⧉ Copy Class Alkene