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Thioacetamide

Thioacetamide

General
Systematic name	Thioacetamide
Other names	acetothioamide, ethanethioamide, TAA, thioacetimidic acid, TA
Molecular formula	C₂H₅NS
SMILES	CC(N)=S
Molar mass	75.13 g/mol
Appearance	colourless crystals, slight mercaptan odor
CAS number	[62-55-5]
Properties
Density and phase	1.269 g/cm³
Solubility in water	good, with hydrolysis
Other solvents	acetonitrile, acetone
Melting point	115 °C
Boiling point	decomp.
Structure
Crystal structure	monoclinic
Dipole moment	? D
Hazards
MSDS	MSDS
Main hazards	stench
NFPA 704
Flash point	?°C
R/S statement	R: R22 R36 R37 R45 S: S45 S53
RTECS number	AC8925000
Supplementary data page
Structure and properties	n, ε_r, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Related compounds
Related compounds	acetamide, dithioacetic acid
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Thioacetamide is an organosulfur compound with the formula CH₃CSNH₂. This white crystalline solid is soluble in water and serves as a source of hydrogen sulfide in the synthesis of organic and inorganic compounds. It is a prototypical thioamide.

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1 Coordination chemistry
2 Preparation
3 Structure
4 Safety
5 References

Coordination chemistry

Thioacetamide was widely used in classical qualitative inorganic analysis as an in situ source for sulfide ions. Thus, treatment of aqueous solutions of many metal cations to a solution of thioacetamide affords the corresponding metal sulfide:

M²⁺ + CH₃C(S)NH₂ + H₂O → MS + CH₃C(O)NH₂ + 2 H⁺ (M = Ni, Pb, Cd, Hg)

Related precipitations occur for sources of soft trivalent cations (As³⁺, Sb³⁺, Bi³⁺) and monovalent cations (Ag⁺, Cu⁺).

Preparation

Thioacetamide is prepared by treating acetamide with phosphorus pentasulfide as shown in the following idealized reaction:^[1]

CH₃C(O)NH₂ + 1/4 P₄S₁₀ → CH₃C(S)NH₂ + 1/4 P₄S₆O₄

Structure

The C₂NH₂S portion of the molecule is planar; the C-S and C-N distances are 1.713 and 1.324 Å, both indicating multiple bonding.^[2]

Safety

Thioacetamide is carcinogen class 2B.

References

^ George Schwarz "2,4-Dimethylthiazole" Organic Syntheses, Collected Volume 3, p.332 (1955). http://www.orgsyn.org/orgsyn/pdfs/CV3P0332.pdf
^ Mary R. Truter "An accurate determination of the crystal structure of thioacetamide" Journal of the Chemical Society, 1960, pp. 997-1007. DOI: 10.1039/JR9600000997

"Thioacetamide (Sulfo amine)". Chemical Land 21. Retrieved on February 14, 2006.

Category: Organosulfur compounds

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Thioacetamide". A list of authors is available in Wikipedia.