Subsulfate

Subsulfate is a nonstandard or context-dependent term that does not have a single, formally defined meaning in modern chemical nomenclature. In literature, it may appear in different ways, and its meaning can vary with the source. Because of this ambiguity, subsulfate is not typically used in formal naming, and readers should rely on explicit composition and oxidation-state information when possible.

Possible interpretations found in some contexts include:

- A reference to species related to sulfate (SO4^2−) where sulfur is in a lower oxidation state, such as sulfite (SO3^2−), though this is not a universally accepted substitution and should be clarified in the source.

- An informal description of partially substituted sulfate derivatives, such as organosulfates or sulfate esters, where one or more components of the sulfate group are replaced or modified.

- In mineralogy, a historical or nonstandard label for minerals containing sulfate groups together with other anions or with structural water, which does not correspond to a widely adopted mineral classification.

Because the standard terms for sulfur-oxygen species are sulfite (SO3^2−) and sulfate (SO4^2−), as well as specific organosulfate or polysulfate derivatives, authorities generally prefer precise names that specify oxidation state and composition. When encountering the term subsulfate, readers should consult the original source for its defined meaning and, for clarity, prefer established terminology in subsequent discussions.

See also: sulfate, sulfite, thiosulfate, organosulfate, sulfate minerals.