Final answer:
The compound Cl2O8 mentioned in the question is incorrect, but Cl2O7 is known as dichlorine heptoxide. Compounds are named based on the type and number of atoms they contain.
Step-by-step explanation:
The molecular formula Cl2O7 does not correspond to the compound name Cl2O8 as given in the question. Instead, Cl2O7 is named dichlorine heptoxide. Naming a compound is based on the elements present and the number of each type of atom in the compound. For example, the compound with the molecular formula CCl4 is named carbon tetrachloride because it contains one carbon atom and four chlorine atoms.