Sodium nitrite (NaNO2) is an ionic compound. It is composed of positively charged sodium ions (Na+) and negatively charged nitrite ions (NO2-). These ions are held together by strong electrostatic forces, forming a stable crystal lattice. Ionic compounds like sodium nitrite are typically hard, brittle, and have high melting points. They also readily dissolve in polar solvents like water, where the ions can dissociate and move freely in the solution. In contrast, molecular compounds are formed by the covalent bonding of atoms and do not dissociate into ions.