Thiocarbonate
Thiocarbonate describes a family of anions with the general chemical formula Template:Chem/link (x = 0, 1, or 2):
- for x = 2 it is monothiocarbonate ion Template:Chem2
- for x = 1 it is dithiocarbonate ion Template:Chem2
- for x = 0 it is trithiocarbonate ion Template:Chem2
Like the carbonate dianion, the thiocarbonate ions are trigonal planar, with carbon atom at the center of triangle, and oxygen and sulfur atoms at the peaks of the triangle. The average bond order between C and S or O is Template:Sfrac. The state of protonation is usually not specified. These anions are good nucleophiles and good ligands.[1][2]
Thiocarbonates refer to salts of those ions as well (e.g. potassium trithiocarbonate, Template:Chem2).
Thiocarbonates refer to esters of those ions as well (e.g. dimethyl trithiocarbonate, Template:Chem2). They contain trigonal planar divalent functional groups Template:Chem/link similar to these anions (x = 0, 1, or 2, R is organyl group). Esters with the formula Template:Chem2 are also called xanthates, while esters with the formula Template:Chem2 are also called thioxanthates.
Thiocarbonates also refer to salts of organyl thiocarbonate ions (e.g. sodium ethyl xanthate or SEX, Template:Chem2). They contain Template:Chem/link anions (x = 0, 1, or 2, R is organyl group). Anions with the formula Template:Chem2, and their salts, are also called xanthates, while salts with the formula Template:Chem2, and their salts, are also called thioxanthates.
Monothiocarbonate
Monothiocarbonate is the dianion Template:Chem2, which has C2v symmetry. Monothiocarbonate arises by the hydrolysis of thiophosgene or the reaction of base with carbonyl sulfide:
The esters of monothiocarbonic acids are called monothiocarbonates as well (e.g. O-ethyl-S-methyl monothiocarbonate Template:Chem2).
Dithiocarbonates
Dithiocarbonate is the dianion Template:Chem2, which has C2v symmetry. It arises from the reaction of aqueous base with carbon disulfide:
Important derivatives of dithiocarbonates are the xanthates (O-esters of dithiocarbonates), with the formula Template:Chem2. These salts are typically prepared by the reaction of sodium alkoxides with carbon disulfide.
Another group of dithiocarbonates have the formula Template:Chem2.[3] They are often derived by hydrolysis of the corresponding trithiocarbonates (RS)2CS. One example is tetrathiapentalenedione, a heterocycle that consists of two dithiocarbonate groups.
Trithiocarbonates
Script error: No such module "Labelled list hatnote". Trithiocarbonate is the dianion Template:Chem2, which has D3h symmetry. Trithiocarbonate is prepared by the reaction of sodium hydrosulfide (NaSH) with carbon disulfide:[4]
The relatively elusive trithiocarbonic acid Template:Chem2 has been characterized by X-ray crystallography.[5]
Esters of thiocarbonic acid, such as dimethyl trithiocarbonate (Template:Chem2) are also called thioxanthate esters. Trithiocarbonate esters inhibit the enzyme carbonic anhydrase.[6]
Perthiocarbonates
Addition of sulfur to trithiocarbonate gives the perthiocarbonate anion Template:Chem2, which contains one sulfur–sulfur bond.[7]
Perthiocarbonic acid (or tetrathioperoxycarbonic acid / disulfanylmethanedithioic acid / CAS#13074-70-9[8]) has never been obtained in pure form.[9]
See also
- Trithiocarbonic acid
- Xanthate
- Thioxanthate
- Sodium ethyl xanthate (SEX)
- Potassium ethyl xanthate (KEX)
- Potassium amyl xanthate
- Potassium trithiocarbonate
- Ethyl xanthic acid
References
<templatestyles src="Reflist/styles.css" />
- ↑ Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. Template:ISBN
- ↑ Script error: No such module "citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "Citation/CS1".(a procedure for synthesis of K2CS3
- ↑ Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
- ↑ Sodium tetrathiocarbonate from PubChem
- ↑ Tetrathioperoxycarbonic acid from PubChem
- ↑ A Text-book of Inorganic Chemistry, Volume 7, Issue 2, 1931, p. 269
Script error: No such module "Check for unknown parameters".