Potassium pyrosulfate is a chemical compound, K₂S₂O₇. It contains the pyrosulfate

Pyrosulfate

In chemistry, disulfate or pyrosulfate is the anion with the molecular formula [S2O7]2−. Disulfate is the IUPAC name. It has a dichromate like structure and can be visualised as two corner sharing SO4 tetrahedra, with a bridging oxygen atom....

 anion S₂O₇²⁻ which has a dichromate like structure and can be visualised as two corner sharing SO₄ tetrahedra, with a bridging oxygen atom. A semi-structural formula for pyrosulfate ion is O₃SOSO₃²⁻. In this compound sulfur has an oxidation state

Oxidation state

In chemistry, the oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. The formal oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic. Oxidation states are typically represented by...

 of +6.

Potassium pyrosulfate is used in analytical chemistry; samples are fused with potassium pyrosulfate, (or a mixture of potassium pyrosulfate and potassium fluoride

Potassium fluoride

Potassium fluoride is the chemical compound with the formula KF. After hydrogen fluoride, KF is the primary source of the fluoride ion for applications in manufacturing and in chemistry. It is an alkali metal halide and occurs naturally as the rare mineral carobbiite...

, KF) to ensure complete dissolution prior to a quantitative analysis.

It is also used as a catalyst in conjunction with vanadium(V) oxide

Vanadium(V) oxide

Vanadium oxide is the chemical compound with the formula V2O5. Commonly known as vanadium pentoxide, this brown/yellow solid is the most stable and common compound of vanadium. Upon heating it reversibly loses oxygen...

, for example.