In terms of structure and bonding, describe Calcium Chloride (CaCl2) and Sulfur Dioxide (SO2) and explain why CaCl2 has a higher melting point than SO2.

Sulfur dioxide has a "simple molecular" structure. It consists of one sulfur atom bonded to two oxygen atoms via double, covalent bonds. Calcium chloride is an ionic compound and is formed by oppositely charged Ca2+ and Cl- ions arranged in an alternating lattice. SO2 only has weak van der Waals forces between molecules which require little energy to overcome and cause the structure to melt. CaCl2 is held together by strong ionic (electrostatic) attractions between ions which require a much greater input of energy to overcome.