Thiocarbonate


Thiocarbonate describes a family of anions with the general chemical formula . Like the carbonate dianion, the thiocarbonates are planar, with carbon at the center. The average bond order from C to S or O is. The state of protonation is usually not specified. These anions are good nucleophiles and good ligands.
Organic compounds containing divalent functional groups similar to these anions are also called thiocarbonates.

Monothiocarbonate

Monothiocarbonate is the dianion CO2S2−, which has C2v symmetry. Monothiocarbonate arises by the hydrolysis of thiophosgene or the reaction of base with carbonyl sulfide:

Dithiocarbonates

Dithiocarbonate is the dianion, which has C2v symmetry. It arises from the reaction of aqueous base with carbon disulfide:
Important derivatives of dithiocarbonates are the xanthates, with the formula. These salts are typically prepared by the reaction of sodium alkoxides with carbon disulfide.
Another group of dithiocarbonates have the formula 2CO. They are often derived by hydrolysis of the corresponding trithiocarbonates 2CS. One example is tetrathiapentalenedione, a heterocycle that consists of two dithiocarbonate groups.

Trithiocarbonates

Trithiocarbonate is the dianion, which has D3h symmetry. Trithiocarbonate is derived from the reaction of sulfide sources with carbon disulfide:
Dimethyl trithiocarbonate, 2CS, is organic and co-valent, not ionic.

Perthiocarbonates

Addition of sulfur to trithiocarbonate gives the perthiocarbonate anion, which contains one sulfur–sulfur bond.
Perthiocarbonic acid has never been synthesized in the pure form but only as a dark brown solution.