Why is the anion suffix -ide used to name molecular compounds?

...It states in my book that all binary compounds,molecular or ionic, all end in -ide. But why is this true if ONLY anions get a different ending? Anish

Anish, your book is correct. Binary molecular compounds are named as though they were ionic. Since one-element anions always have an -ide ending, binary molecular compounds will always have an -ide ending too.

But there is a difference in the way binary molecular and binary ionic compounds are named. Because there are often many different molecular binary compounds for the same two elements, numerical prefixes (mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca, undeca, and dodeca) are usually used with molecular compounds. The prefixes are usually omitted in ionic compound names, because the names of the cations and anions are usually all you need to know to work out the stoichiometry of the compound. For example, the molecular compounds SF₄ and SF₆ are sulfur tetrafluoride and sulfur hexafluoride; but the ionic compounds FeF₂ and FeF₃ are iron(II) fluoride and iron(III) fluoride.

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General Chemistry Online! Why is the anion suffix -ide used to name molecular compounds?