In naming molecular compounds, which element name comes first?

In naming molecular compounds, the convention is to name the more positive element first. This principle reflects the underlying nature of the compounds being composed of nonmetals, where the more electropositive (or less electronegative) element tends to be listed at the beginning of the name. Typically, this element is often closer to the left side of the periodic table, thus reflecting its tendency to lose electrons and form positive ions, even in covalent bonding contexts.

For example, in a compound like carbon monoxide (CO), carbon, being less electronegative than oxygen, is named first. This convention also helps provide clarity when discussing the structure and properties of the compound, as it indicates the relative positions of the elements in terms of their reactivity and bonding behavior. Naming the more negative element first would contradict the established nomenclature for molecular compounds and create confusion regarding the identity and characteristics of the compound. Therefore, the correct practice is to begin with the more positive element when naming.