If Chlorine's formula is Cl2, why is Lithium Chloride LiCl?

Chlorine and every other molecule in the VIIA column is a diatomic molecule. Meaning in nature chlorine is never found as a single chlorine molecule, it is found bonded to another chlorine molecule (its more stable that way). We represent that by writing Cl2 when its in its natural form. However when chlorine reacts with another molecule, one chlorine dissociates from the other and reacts. So when chlorine reacts with Lithium only one atom of chlorine from the diatomic molecule of chlorines can react with the lithium since lithium has an oxidation state of +1. Molecules like Calcium with an oxidation state of +2 can react with two chlorine atoms and thus both atoms from the diatomic molecule can be reacted resulting in CaCl2