Disulfuric acid

Disulfuric acid (alternative spelling disulphuric acid) or pyrosulfuric acid (alternative spelling pyrosulphuric acid), also named oleum is an oxyacid 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 ⇌ H2S2O7 The acid is prepared by reacting excess SO3 with sulfuric acid: H2SO4 + SO3 → H2S2O7 There are other related acids with the general formula H2O·(SO3)x though none are isolable.

Disulfuric acid

Disulfuric acid (alternative spelling disulphuric acid) or pyrosulfuric acid (alternative spelling pyrosulphuric acid), also named oleum is an oxyacid 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 ⇌ H2S2O7 The acid is prepared by reacting excess SO3 with sulfuric acid: H2SO4 + SO3 → H2S2O7 There are other related acids with the general formula H2O·(SO3)x though none are isolable.