Binary compounds consist of only two distinct elements, regardless of whether the compound is ionic or molecular. Water is a binary compound, as are calcium chloride, ammonia, and potassium iodide.
An ionic binary compound consists of cations of one element and anions of another. KI is an ionic binary compound, composed of K cations and I anions.
A molecular binary compound does not consist of discrete ions, but of molecules. H2O is molecular, as is NH3.
