Iodoform: Difference between revisions

{{for|use of the term "iodoform" in cryptography|Group key}}

{{Use dmy dates|date=April 2017}}

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 444991229

| ImageFile = Iodoform.svg

| ImageFile_Ref = {{chemboximage|correct|??}}

| ImageSize = 100

| ImageName = Stereo, skeletal formula of iodoform with the explicit hydrogen added

| ImageFileL1 = Iodoform-GED-3D-balls.png

| ImageFileL1_Ref = {{chemboximage|correct|??}}

| ImageNameL1 = Ball and stick model of iodoform

| ImageFileR1 = Iodoform-GED-3D-vdW.png

| ImageFileR1_Ref = {{chemboximage|correct|??}}

| ImageFile2_Ref = {{chemboximage|correct|??}}

| ImageFile2 = Iodoform in a test tube.jpg

| ImageSize2 =

| ImageName2 = Freshly made iodoform from an iodine tincture.

| PIN = Triiodomethane

| OtherNames = {{ubl|Iodoform<ref name=iupac2013>{{cite book | title = Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 (Blue Book) | publisher = [[Royal Society of Chemistry|The Royal Society of Chemistry]] | date = 2014 | location = Cambridge | page = 661 | doi = 10.1039/9781849733069-FP001 | isbn = 978-0-85404-182-4 | quote = The retained names ‘bromoform’ for HCBr₃, ‘chloroform’ for HCCl₃, and ‘iodoform’ for HCI₃ are acceptable in general nomenclature. Preferred IUPAC names are substitutive names.| chapter = Front Matter }}</ref>|Carbon hydride triiodide|Carbon triiodide<ref name=pubchem>{{cite web | url=https://pubchem.ncbi.nlm.nih.gov/compound/Iodoform | title=Iodoform }}</ref>}}

| Section1 = {{Chembox Identifiers

| CASNo_Ref = {{cascite|correct|CAS}}

| PubChem = 6374

| ChemSpiderID = 6134

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| UNII_Ref = {{fdacite|correct|FDA}}

| EINECS = 200-874-5

| KEGG_Ref = {{keggcite|correct|kegg}}

| MeSHName = iodoform

| ChEBI = 37758

| ChEBI_Ref = {{ebicite|correct|EBI}}

| ChEMBL = 1451116

| ChEMBL_Ref = {{ebicite|changed|EBI}}

| RTECS = PB7000000

| Beilstein = 1697010

| SMILES = IC(I)I

| StdInChI = 1S/CHI3/c2-1(3)4/h1H

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| StdInChIKey = OKJPEAGHQZHRQV-UHFFFAOYSA-N

| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

| Section2 = {{Chembox Properties

| C=1|H=1|I=3

| Appearance = Pale, light yellow, opaque crystals

| Odor = Saffron-like<ref name=GESTIS>{{GESTIS|ZVG= 491168}}</ref>

| Density = 4.008 g/cm³<ref name=GESTIS/>

| MeltingPtC = 119

| MeltingPt_ref =<ref name=GESTIS/>

| BoilingPtC = 218

| BoilingPt_ref =<ref name=GESTIS/>

| Solubility = 100 mg/L<ref name=GESTIS/>

| Solvent1 = diethyl ether

| Solubility1 = 136 g/L

| Solvent2 = acetone

| Solubility2 = 120 g/L

| Solvent3 = ethanol

| Solubility3 = 78 g/L

| LogP = 3.118

| HenryConstant = 3.4 μmol·Pa⁻¹·kg⁻¹

| MagSus = −117.1·10⁻⁶ cm³/mol

}}

| Section3 = {{Chembox Structure

| CrystalStruct = Hexagonal

| MolShape = [[Tetrahedral molecular geometry|Tetrahedral]] at [[carbon|C]]

}}

| Section5 = {{Chembox Thermochemistry

| DeltaHf = 180.1 – 182.1 kJ/mol

| DeltaHc = −716.9 – −718.1 kJ/mol

| HeatCapacity = 157.5 J/(K·mol)

}}

| Section6 = {{Chembox Pharmacology

| ATCCode_prefix = D09

| ATCCode_suffix = AA13

}}

| Section7 = {{Chembox Hazards

| GHSPictograms = {{gHS exclamation mark}}

| GHSSignalWord = '''WARNING'''

| HPhrases = {{h-phrases|315|319|335}}

| PPhrases = {{p-phrases|261|280|305+351+338}}

| NFPA-H = 2

| NFPA-F = 1

| NFPA-R = 1

| FlashPtC = 204

| LD50 = {{ubl|355 mg/kg (oral, rat)<ref name=GESTIS/>|1180 mg/kg (dermal, rat)<ref name=GESTIS/>|1.6 mmol/kg([[subcutaneous injection|s.c.]], mouse)<ref name=Merck>''[[Merck Index]]'', 12 Edition, '''5054'''</ref>}}

| IDLH = N.D.<ref name=PGCH>{{PGCH|0343}}</ref>

| REL = 0.6 ppm (10 mg/m³)<ref name=PGCH/>

| PEL = none<ref name=PGCH/>

}}

| Section8 = {{Chembox Related

| OtherFunction_label = haloalkanes

| OtherCompounds = {{ubl||[[Methyl iodide]]|[[Diiodomethane]]|[[Carbon tetraiodide]]|[[Fluoroform]]|[[Chloroform]]|[[Bromoform]]}}

}}

}}

[[File:Iodoform.jpg|thumb|Iodoform stored in an [[ampoule]]]]

'''Iodoform''' (also known as '''triiodomethane''') is the [[organoiodine compound]] with the [[chemical formula]] {{chem2|CHI3|auto=1}}. 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]].

==Naming==

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,<ref name="pubchem" /> but the IUPAC recommends against doing so, as "carbon triiodide" could also mean {{chem2|C2I6}} ([[hexaiodoethane]], a highly unstable compound).

== Structure ==

The molecule adopts a [[tetrahedral molecular geometry|tetrahedral geometry]] with C_3v [[symmetry group|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;<ref>{{citation| first = Georges-Simon|last = Surellas| url = http://gallica.bnf.fr/ark:/12148/bpt6k6137757n/f2.image |title = Notes sur l'Hydriodate de potasse et l'Acide hydriodique. -- Hydriodure de carbone; moyen d'obtenir, à l'instant, ce composé triple|trans-title= Notes on the hydroiodide of potassium and on hydroiodic acid -- hydroiodide of carbon; means of obtaining instantly this compound of three elements| language = French| publisher = Metz, France: Antoine| year= 1822| pages= 17–20, 28–29}}</ref> and at much the same time independently by [[John Thomas Cooper]].<ref name=ODNB>{{cite ODNB|last=James|first=Frank A. J. L.|title=Cooper, John Thomas |url=http://www.oxforddnb.com/view/article/39361 |access-date=26 January 2012 |doi=10.1093/ref:odnb/39361|year=2004}}</ref> 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]] ({{chem2|CH3COR}}), [[acetaldehyde]] ({{chem2|CH3CHO}}), [[ethanol]] ({{chem2|CH3CH2OH}}), and certain secondary [[Alcohol (chemistry)|alcohol]]s ({{chem2|CH3CHROH}}, where R is an alkyl or aryl group).

The reaction of iodine and base with [[methyl]] [[ketone]]s 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 alcohol]]s containing at least one [[methyl]] group in [[Alpha and beta carbon|alpha-position]].

Some reagents (e.g. [[hydrogen iodide]]) convert iodoform to [[diiodomethane]]. Also conversion to [[carbon dioxide]] is possible: 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.

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

The compound finds small-scale use as a disinfectant.<ref name=Merck/><ref>{{citation| first = Phyllis A.| last = Lyday |publisher = Wiley-VCH, Weinheim| year = 2005 | doi = 10.1002/14356007.a14_381.pub2 | title = Ullmann's Encyclopedia of Industrial Chemistry | pages = 1–13 | isbn = 9783527306732 | chapter = Iodine and Iodine Compounds }}</ref> 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 [[antiseptic]]s, it is still used in [[otolaryngology]] in the form of [[bismuth subnitrate]] iodoform [[Liquid paraffin (drug)|paraffin]] paste (BIPP) as an antiseptic packing for cavities. It is the active ingredient in many ear powders for [[dog]]s and [[cat]]s, along with [[zinc oxide]] and [[propionic acid]], which are used to prevent infection and facilitate removal of ear hair.{{Citation needed|date=October 2014}}

==See also==

* [[Fluoroform]]

* [[Chloroform]]

* [[Bromoform]]

==References==

Randhawa GK, Graham R, Matharu KS, Bismuth Iodoform Paraffin Paste: History and uses. British Journal of Oral and Maxillofacial Surgery. 2019;67:E53-E54.

{{Reflist}}

==External links==

* {{PGCH|0343}}

* [http://hazard.com/msds/mf/baker/baker/files/i3480.htm MSDS at JT Baker]

* [http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/1952/74/i09/f-pdf/f_ja01129a067.pdf?sessid=6006l3 A Method for the Specific Conversion of Iodoform to Carbon Dioxide]

* [https://www.creative-chemistry.org.uk/documents/N-ch3-16.pdf Preparation]

* {{Cite EB1911 |wstitle=Iodoform |volume=14 |page=726 |short=1}}

{{medicated dressings}}

{{halomethanes}}

{{Authority control}}

[[Category:Iodoalkanes]]

[[Category:Iodine-containing natural products]]