Thioacetamide

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Thioacetamide
IUPAC name Thioacetamide
Other names acetothioamide, ethanethioamide, TAA, thioacetimidic acid, TA
Identifiers
CAS number [62-55-5]
RTECS number AC8925000
SMILES CC(N)=S
Properties
Molecular formula C2H5NS
Molar mass 75.13 g/mol
Appearance colourless crystals, slight mercaptan odor
Density 1.269 g/cm³
Melting point

115 °C
Boiling point

decomp.
Solubility in water good, with hydrolysis
Structure
Crystal structure monoclinic
Hazards
MSDS MSDS
Main hazards stench
R-phrases R22 R36 R37 R45
S-phrases S45 S53
Flash point  ?°C
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.

Contents

[edit] 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+).

[edit] 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

[edit] 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]

[edit] Safety

Thioacetamide is carcinogen class 2B.

[edit] References

 The references in this article would be clearer with a different or consistent style of citation, footnoting, or external linking.
  1. ^ George Schwarz "2,4-Dimethylthiazole" Organic Syntheses, Collected Volume 3, p.332 (1955). http://www.orgsyn.org/orgsyn/pdfs/CV3P0332.pdf
  2. ^ 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