Thiocarbonic acid is an inorganic acid which is an analog of carbonic acid (or ), in which all oxygen atoms are replaced with sulfur atoms. It is an unstable hydrophobic red oily liquid with the chemical formula (or ). It is often referred to as trithiocarbonic acid so as to differentiate it from other carbonic acids containing sulfur, such as monothiocarbonic O,O-acid , monothiocarbonic O,S-acid , dithiocarbonic O,S-acid and dithiocarbonic S,S-acid (see thiocarbonates). Discovery and synthesis It was first reported in brief by Zeise in 1824 and later in more detail by Berzelius in 1826, in both cases it was produced by the action of carbon disulfide on a hydrosulfide salt (e.g. potassium hydrosulfide). CS2 + 2 KSH → K2CS3 + H2S Treatment with acids liberates the thiocarbonic acid as a red oil K2CS3 + 2 HX → H2CS3 + 2 KX Both the acid and many of its salts are unstable and decompose via the release of carbon disulfide, particularly upon heating: H2CS3 → CS2 + H2S Applications Thiocarbonic acid currently has no significant applications. Its esters, which are sometimes called thioxanthates, find use in RAFT polymerization. References Hydrogen compounds Sulfur(−II) compounds Inorganic carbon compounds