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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, εr, 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.

Contents

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

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