Tags: Chemical Compound, Chemical Substance.
Disulfuric acid (or pyrosulfuric acid) is an oxoacid of sulfur. It is a major constituent of fuming sulfuric acid oleum and this is how most chemists encounter it. It is also a minor constituent of liquid anhydrous sulfuric acid due to the equilibria:H2SO4 ⇌ H2O + SO3SO3 + H2SO4 ⇌ H2S2O7The acid is prepared by reacting excess SO3 with sulfuric acid:H2SO4 + SO3 → H2S2O7Disulfuric acid can be seen as the sulfuric acid analogue of an acid anhydride.
