Which of the following compounds does not have similarity in their structural aspect? — s Block Elements Chemistry Question

💡 Solution & Explanation

Step 1: Look at the crystalline forms of the compounds. FeSO4.7H2O, MgSO4.7H2O, and ZnSO4.7H2O are heptahydrated transition/alkaline earth metal sulfates which crystallize in isomorphous monoclinic/orthorhombic systems (often known as vitriols, e.g., green vitriol, Epsom salt, white vitriol). Step 2: Na2CO3.7H2O is a sodium carbonate heptahydrate, which has a completely different structural network and lattice geometry because of the presence of monovalent sodium cations and planar carbonate anions instead of divalent cations and tetrahedral sulfate anions. Step 3: Thus, Na2CO3.7H2O does not share structural similarities with the other three sulfate salts. This corresponds to option (b).