Final answer:
LiBr does not represent a molecular compound; it is an ionic compound because it is made up of lithium (metal) and bromine (nonmetal).
Step-by-step explanation:
The student is inquiring about which of the provided options does not represent a molecular compound. Molecular compounds, also known as covalent compounds, are formed when nonmetal atoms share electrons to form discrete molecules with covalent bonds. Examples include water (H₂O) and carbon dioxide (CO₂). On the other hand, ionic compounds like sodium chloride (NaCl) are formed from the electrostatic attraction between cations and anions, which result from the transfer of electrons from metal to nonmetal atoms. Here, the substance that does not represent a molecular compound is LiBr, as it is an ionic compound composed of lithium (a metal) and bromine (a nonmetal). The formulas for molecular compounds generally display the number of each type of atom in a molecule, whereas the formula for an ionic compound represents the relative number of ions rather than discrete molecules.