Iodoform

Iodoform
Ball and stick model of iodoform
Names
	Preferred IUPAC name Triiodomethane
	Other names Iodoform; Carbon hydride triiodide; Carbon triiodide;
Identifiers
CAS Number	75-47-8 ;
3D model (JSmol)	Interactive image;
Beilstein Reference	1697010
ChEBI	CHEBI:37758 ;
ChEMBL	ChEMBL1451116 ;
ChemSpider	6134 ;
ECHA InfoCard	100.000.795
EC Number	200-874-5;
KEGG	D01910 ;
MeSH	iodoform
PubChem CID	6374;
RTECS number	PB7000000;
UNII	KXI2J76489 ;
CompTox Dashboard (EPA)	DTXSID4020743 ;
	InChI InChI=1S/CHI3/c2-1(3)4/h1H Key: OKJPEAGHQZHRQV-UHFFFAOYSA-N ;
	SMILES IC(I)I;
Properties
Chemical formula	CHI3
Molar mass	393.732 g·mol−1
Appearance	Pale, light yellow, opaque crystals
Odor	Saffron-like
Density	4.008 g/cm3
Melting point	119 °C (246 °F; 392 K)
Boiling point	218 °C (424 °F; 491 K)
Solubility in water	100 mg/L
Solubility in diethyl ether	136 g/L
Solubility in acetone	120 g/L
Solubility in ethanol	78 g/L
log P	3.118
Henry's law; constant (kH)	3.4 μmol·Pa−1·kg−1
Magnetic susceptibility (χ)	−117.1·10−6 cm3/mol
Structure
Crystal structure	Hexagonal
Molecular shape	Tetrahedral at C
Thermochemistry
Heat capacity (C)	157.5 J/(K·mol)
Std enthalpy of; formation (ΔfH⦵298)	180.1 – 182.1 kJ/mol
Std enthalpy of; combustion (ΔcH⦵298)	−716.9 – −718.1 kJ/mol
Pharmacology
ATC code	D09AA13 (WHO)
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
Precautionary statements	P261, P280, P305+P351+P338
NFPA 704 (fire diamond)	2 1 1
Flash point	204 °C (399 °F; 477 K)
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	355 mg/kg (oral, rat); 1180 mg/kg (dermal, rat); 1.6 mmol/kg(s.c., mouse);
	NIOSH (US health exposure limits):
PEL (Permissible)	none
REL (Recommended)	0.6 ppm (10 mg/m3)
IDLH (Immediate danger)	N.D.
Related compounds
Related compounds	Methyl iodide; Diiodomethane; Carbon tetraiodide; Fluoroform; Chloroform; Bromoform;
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Iodoform (also known as triiodomethane) is the organoiodine compound with the chemical formula C H I₃. It is a pale yellow, crystalline, volatile substance, with a penetrating and distinctive odor (in older chemistry texts, the smell is sometimes referred to as that of hospitals, where the compound is still commonly used) and, analogous to chloroform, sweetish taste. It is occasionally used as a disinfectant.

Quick Facts Names, Identifiers ...

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The name iodoform originates with the "formyle radical," an archaic term for the HC moiety, and is retained for historical consistency. A full, modern name is triiodomethane. The "hydride" in the latter is sometimes omitted,^[2] but the IUPAC recommends against doing so, as "carbon triiodide" could also mean C₂I₆ (hexaiodoethane, a highly unstable compound).

The molecule adopts a tetrahedral geometry with C_3v symmetry.

The synthesis of iodoform was first described by Georges-Simon Serullas in 1822, by reactions of iodine vapour with steam over red-hot coals, and also by reaction of potassium with ethanolic iodine in the presence of water;^[6] and at much the same time independently by John Thomas Cooper.^[7] It is synthesized in the haloform reaction by the reaction of iodine and sodium hydroxide with any one of these four kinds of organic compounds: a methyl ketone (CH₃COR), acetaldehyde (CH₃CHO), ethanol (CH₃CH₂OH), and certain secondary alcohols (CH₃CHROH, where R is an alkyl or aryl group).

The reaction of iodine and base with methyl ketones is so reliable that the iodoform test (the appearance of a yellow precipitate) is used to probe the presence of a methyl ketone. This is also the case when testing for specific secondary alcohols containing at least one methyl group in alpha-position.

Some reagents (e.g. hydrogen iodide) convert iodoform to diiodomethane. Also conversion to carbon dioxide is possible:^[8] Iodoform reacts with aqueous silver nitrate to produce carbon monoxide. When treated with powdered elemental silver the iodoform is reduced, producing acetylene. Upon heating iodoform decomposes to produce diatomic iodine, hydrogen iodide gas, and carbon.

Natural occurrence

The angel's bonnet mushroom contains iodoform, and shows its characteristic odor.

The compound finds small-scale use as a disinfectant.^[4]^[9] Around the beginning of the 20th century, it was used in medicine as a healing and antiseptic dressing for wounds and sores and, although this use is now largely superseded by superior antiseptics, it is still used in otolaryngology in the form of bismuth subnitrate iodoform paraffin paste (BIPP) as an antiseptic packing for cavities.^[10] It is the active ingredient in many ear powders for dogs and cats, along with zinc oxide and propionic acid, which are used to prevent infection and facilitate removal of ear hair.^{[citation needed]}

[1]
"Front Matter". Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 661. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4. The retained names 'bromoform' for HCBr₃, 'chloroform' for HCCl₃, and 'iodoform' for HCI₃ are acceptable in general nomenclature. Preferred IUPAC names are substitutive names.
[2]
"Iodoform".
[3]
Record in the GESTIS Substance Database of the Institute for Occupational Safety and Health
[4]
Merck Index, 12 Edition, 5054
[5]
NIOSH Pocket Guide to Chemical Hazards. "#0343". National Institute for Occupational Safety and Health (NIOSH).
[6]
Surellas, Georges-Simon (1822), Notes sur l'Hydriodate de potasse et l'Acide hydriodique. -- Hydriodure de carbone; moyen d'obtenir, à l'instant, ce composé triple [Notes on the hydroiodide of potassium and on hydroiodic acid -- hydroiodide of carbon; means of obtaining instantly this compound of three elements] (in French), Metz, France: Antoine, pp. 17–20, 28–29
[7]
James, Frank A. J. L. (2004). "Cooper, John Thomas". Oxford Dictionary of National Biography (online ed.). Oxford University Press. doi:10.1093/ref:odnb/39361. Retrieved 26 January 2012. (Subscription or UK public library membership required.)
[8]
Shreeve, W. W.; Leaver, F.; Siegel, I. (1952). "A Method for the Specific Conversion of Iodoform to Carbon Dioxide". J. Am. Chem. Soc. 74 (9): 2404. doi:10.1021/ja01129a067.
[9]
Lyday, Phyllis A. (2005), "Iodine and Iodine Compounds", Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, pp. 1–13, doi:10.1002/14356007.a14_381.pub2, ISBN 9783527306732
[10]
Randhawa, G. K.; Graham, R.; Matharu, K. S. (2019). "Bismuth Iodoform Paraffin Paste: History and uses". British Journal of Oral and Maxillofacial Surgery. 57 (10): E53–E54. doi:10.1016/j.bjoms.2019.10.153.

NIOSH Pocket Guide to Chemical Hazards. "#0343". National Institute for Occupational Safety and Health (NIOSH).
Preparation
"Iodoform" . Encyclopædia Britannica. Vol. 14 (11th ed.). 1911. p. 726.

[iupac2013-1] [1]
"Front Matter". Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 661. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4. The retained names 'bromoform' for HCBr₃, 'chloroform' for HCCl₃, and 'iodoform' for HCI₃ are acceptable in general nomenclature. Preferred IUPAC names are substitutive names.

[pubchem-2] [2]
"Iodoform".

[GESTIS-3] [3]
Record in the GESTIS Substance Database of the Institute for Occupational Safety and Health

[Merck-4] [4]
Merck Index, 12 Edition, 5054

[PGCH-5] [5]
NIOSH Pocket Guide to Chemical Hazards. "#0343". National Institute for Occupational Safety and Health (NIOSH).

[6] [6]
Surellas, Georges-Simon (1822), Notes sur l'Hydriodate de potasse et l'Acide hydriodique. -- Hydriodure de carbone; moyen d'obtenir, à l'instant, ce composé triple [Notes on the hydroiodide of potassium and on hydroiodic acid -- hydroiodide of carbon; means of obtaining instantly this compound of three elements] (in French), Metz, France: Antoine, pp. 17–20, 28–29

[ODNB-7] [7]
James, Frank A. J. L. (2004). "Cooper, John Thomas". Oxford Dictionary of National Biography (online ed.). Oxford University Press. doi:10.1093/ref:odnb/39361. Retrieved 26 January 2012. (Subscription or UK public library membership required.)

[8] [8]
Shreeve, W. W.; Leaver, F.; Siegel, I. (1952). "A Method for the Specific Conversion of Iodoform to Carbon Dioxide". J. Am. Chem. Soc. 74 (9): 2404. doi:10.1021/ja01129a067.

[9] [9]
Lyday, Phyllis A. (2005), "Iodine and Iodine Compounds", Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, pp. 1–13, doi:10.1002/14356007.a14_381.pub2, ISBN 9783527306732

[10] [10]
Randhawa, G. K.; Graham, R.; Matharu, K. S. (2019). "Bismuth Iodoform Paraffin Paste: History and uses". British Journal of Oral and Maxillofacial Surgery. 57 (10): E53–E54. doi:10.1016/j.bjoms.2019.10.153.

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Natural occurrence

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Iodoform

Natural occurrence

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Naming

Structure

Synthesis and reactions

Applications

See also

References

External links