Orthocarbonic acid or methanetetraol is the name given to a hypothetical compound with the chemical formula H4CO4 or C(OH)4. Its molecular structure consists of a single carbon atom bonded to four hydroxyl groups. It would be therefore a fourfold alcohol. In theory it could lose four protons to give the hypothetical oxocarbon anion CO44− (orthocarbonate), and is therefore considered an oxoacid of carbon.
The compound is believed to be highly unstable, decomposing spontaneously into carbonic acid monohydrate.
Orthocarbonic acid is one of the group of carboxylic ortho acids that have the general structure of RC(OH)3.The term ortho acid is also used to refer to the most hydroxylated acid in a set of oxoacids.
Read more about Orthocarbonic Acid: Orthocarbonate Anions, Orthocarbonate Esters