Bisulfate

Part of speech: noun

Definitions

1. A chemical salt formed when one hydrogen of sulfuric acid is replaced by a metal or other cation, leaving the hydrogen sulfate group intact
2. Any compound derived from sulfuric acid in which the hydrogen sulfate ion, HSO4 minus, is paired with a positive ion
3. An acidic salt of sulfuric acid, such as sodium bisulfate, that retains one replaceable hydrogen atom in its structure

Etymology: Bisulfate is a plain chemical coinage, built from the prefix "bi-" and "sulfate." The prefix comes from Latin "bi-", meaning "two" or "twice," which is the same root that gives English words like "bicycle" and "binary." In chemistry, the prefix signals that a salt contains a hydrogen sulfate group, a sulfate ion with one of its oxygen-bonded hydrogens still in place, and that it is therefore acidic. The sulfate part refers to the sulfate ion, whose name derives from "sulfur," the element at its centre. The "two" in the prefix is a little misleading for modern readers. Rather than marking two sulfate units, "bi-" in this compound reflects an older chemical system in which a salt was described as a combination of a base with an extra acid unit, so a bisulfate was a sulfate carrying an additional acid group. Its meaning therefore comes from chemical nomenclature rather than from any everyday sense of the number.

Synonyms: hydrogen sulfate