{{for|use of the term "iodoform" in cryptography|Group key}} {{Use dmy dates|date=April 2017}} {{chembox | Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 444991229 | ImageFile = Iodoform.svg | ImageClass = skin-invert | ImageFile_Ref = {{chemboximage|correct|??}} | ImageSize = 100 | ImageName = Stereo, skeletal formula of iodoform with the explicit hydrogen added | ImageFileL1 = Iodoform-GED-3D-balls.png | ImageClassL1 = bg-transparent | ImageFileL1_Ref = {{chemboximage|correct|??}} | ImageNameL1 = Ball and stick model of iodoform | ImageFileR1 = Iodoform-GED-3D-vdW.png | ImageClassR1 = bg-transparent | 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 = 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 HCBr<sub>3</sub>, ‘chloroform’ for HCCl<sub>3</sub>, and ‘iodoform’ for HCI<sub>3</sub> are acceptable in general nomenclature. Preferred IUPAC names are substitutive names.| chapter = Front Matter }}</ref>}} | Section1 = {{Chembox Identifiers | CASNo = 75-47-8 | CASNo_Ref = {{cascite|correct|CAS}} | PubChem = 6374 | ChemSpiderID = 6134 | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | UNII = KXI2J76489 | UNII_Ref = {{fdacite|correct|FDA}} | EINECS = 200-874-5 | KEGG = D01910 | 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, sweetish<ref name=GESTIS>{{GESTIS|ZVG= 491168}}</ref> | Density = 4.008 g/cm<sup>3</sup><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<sup>−1</sup>·kg<sup>−1</sup> | MagSus = −117.1·10<sup>−6</sup> cm<sup>3</sup>/mol }} | Section3 = {{Chembox Structure | CrystalStruct = Hexagonal | MolShape = Tetrahedral at 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(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/m<sup>3</sup>)<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 sweetish and chloroform-like 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,<ref>{{cite book |last1=Raige-Delorme |first1=Jacques |author-link1=Jacques Raige-Delorme |last2=Bouley |first2=H. |author-link2=Henri Marie Bouley |last3=Daremberg |first3=C. |author-link3=Charles Victor Daremberg |last4=Mignon |first4=J. |last5=Lamy |first5=Charles |title=Nouveau Dictionnaire lexicographique et descriptif des Sciences médicales et vétérinaires ... avec planches intercalées dans le texte, suivi d'un vocabulaire biographique. Par Messieurs Raige-Delorme, H. Bouley, C. Daremberg, J. Mignon, avec la collaboration de M. Ch. Lamy, pour la Chimie |date=1863 |page=520 |url=https://books.google.com/books?id=1HhZAAAAcAAJ&pg=PA520&dq=formyle <!--https://catalog.hathitrust.org/Record/002071479--> |language=fr |quote=Formyle, s. m. Nom donné par Liebig au radical hypothétique (C<sup>2</sup>H) de l'ac. formique, du chloroforme, du bromoforme, de l'iodoforme, etc. |trans-quote=Formyle, masculine noun. Name given by Liebig to the hypothetical radical (C<sup>2</sup>H) of formic acid, chloroform, bromoform, iodoform, etc.}}</ref><ref>At the time, the atomic weight of carbon was thought to be half of its true value: {{cite book |last1=Rocke |first1=Alan J. |author-link1=:de:Alan Rocke |title=The quiet revolution: Hermann Kolbe and the science of organic chemistry |date=1993 |publisher=University of California Press |location=Berkeley |isbn=9780520081109 |page=158 |url=https://publishing.cdlib.org/ucpressebooks/view?docId=ft5g500723&chunk.id=d0e4303&toc.depth=1&toc.id=0&brand=ucpress&query=equivalent+weight+formulas}}</ref> and is retained for historical consistency. A full, modern name is triiodomethane.

== Structure == The molecule adopts a tetrahedral geometry with C<sub>3v</sub> symmetry.

==Synthesis and reactions== 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 alcohols ({{chem2|CH3CHROH}}, where R is an alkyl or aryl group).

:450px|class=skin-invert-image

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. Conversion to carbon dioxide is also possible.<ref>{{cite journal |doi= 10.1021/ja01129a067 |title= A Method for the Specific Conversion of Iodoform to Carbon Dioxide |journal= J. Am. Chem. Soc. |year= 1952 |volume= 74 |issue= 9 |pages= 2404 |first1= W. W. |last1= Shreeve |first2= F. |last2= Leaver |first3= I. |last3= Siegel |bibcode= 1952JAChS..74.2404S }}</ref> 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.

==Applications== 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 safer antiseptics,<ref name=Gottardi2001>{{cite book |author-last=Gottardi |author-first=Waldemar |editor-last=Block |editor-first=Seymour Stanton |chapter=Iodine and Iodine Compounds |title=Disinfection, Sterilization, and Preservation |publisher=Lippincott Williams & Wilkins |date=1 January 2001 |page=176 |isbn=978-0-683-30740-5 |edition=5th |url=https://books.google.com/books?id=3f-kPJ17_TYC&pg=PA176&dq=iodoform |chapter-url=https://archive.org/details/disinfectionster0000unse_n5r4/page/176/mode/2up?q=iodoform}}</ref> it is still used in otolaryngology in the form of bismuth subnitrate iodoform paraffin paste (BIPP) as an antiseptic packing for cavities.<ref>{{cite journal |last1= Randhawa |first1= G. K. |last2= Graham |first2= R. |last3= Matharu |first3= K. S. |title= Bismuth Iodoform Paraffin Paste: History and uses |journal= British Journal of Oral and Maxillofacial Surgery |year= 2019 |volume= 57 |issue= 10 |pages= E53–E54 |doi= 10.1016/j.bjoms.2019.10.153 }}</ref> It is the active ingredient in many ear powders for dogs and cats, along with zinc oxide and boric acid, which are used to prevent infection and facilitate removal of ear hair.{{Citation needed|date=October 2014}}

==See also== * Fluoroform * Chloroform * Bromoform

==References== {{Reflist}}

==External links== * {{PGCH|0343}} * [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:Halomethanes Category:Antiseptics Category:Iodine-containing natural products Category:Organoiodides