Ineed asap : ) which of the following is an ionic compound? a-)co b-) o2 c-) libr d-) nh3 in advance! < 3

C)

Explanations

Approach A: Comparison of the bonding atoms

What element(s) does each species comprise?

Lithium bromide is the only substance that features a metal element bonded to a nonmetal element among all four species in the list. It takes significant differences in electronegativity for the bonding atoms in a binary compound to ionize and form an ionic compound. Therefore the species in question shall  contain at least one metal element bonded to one nonmetal.

Approach B: Comparison of melting points

Recall the physical state of the species under room temperature and pressure:

Ionic bonds hold ions in an ionic compound in place with great degrees of rigidity. In contrast, covalent molecules adhere to each other with intermolecular interactions that are weaker by magnitudes. It's unlikely for ionic crystals to behave as gases under standard conditions. Thus A, B, D cannot be ionic compounds.