It is an unstable hydrophobic red oily liquid.

[1] 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 S=C(OH)2, monothiocarbonic O,S-acid O=C(OH)(SH), dithiocarbonic O,S-acid S=C(OH)(SH) and dithiocarbonic S,S-acid O=C(SH)2 (see thiocarbonates).

It was first reported in brief by Zeise in 1824 and later in more detail by Berzelius in 1826,[2] in both cases it was produced by the action of carbon disulfide on a hydrosulfide salt (e.g. potassium hydrosulfide).

[1] Despite its lability, crystals of thiocarbonic acid have been examined by X-ray crystallography, which confirms the anticipated molecular structure of a trigonal planar molecular geometry at the central carbon atom.

Thiocarbonic acid reacts with bifunctional reagents to give rings.