Aluminium iodide: Difference between revisions

{{short description|Chemical compound}}

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 449832810

| ImageFile = Aluminium-iodide-3D-balls.png

| ImageSize =

| ImageName = Ball and stick model of aluminium iodide dimer

| ImageFile2 = Jodid hlinitý.PNG

| PIN = Aluminium iodide

| OtherNames = Aluminium(III) iodide<br />

|Section1={{Chembox Identifiers

| InChI =

| InChIKey =CECABOMBVQNBEC-DFZHHIFOAE

| CASNo_Ref = {{cascite|correct|??}}

| CASNo_Comment = (anhydrate)

| CASNo1_Ref = {{cascite|correct|??}}

| CASNo1 = 10090-53-6

| CASNo1_Comment = (hexahydrate)

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

| UNII = L903Z8J9VR

| UNII_Comment = (anhydrate)

| UNII1_Ref = {{fdacite|correct|FDA}}

| UNII1 = VWS43EUO9V

| UNII1_Comment = (hexahydrate)

| PubChem = 82222

| PubChem_Comment = (anhydrate)

| ChemSpiderID = 74202

| ChemSpiderID_Comment = (anhydrate)

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

| EINECS = 232-054-8

| UNNumber = UN 3260

| SMILES = I[Al](I)I

| SMILES1 = I[Al-]1(I)[I+][Al-]([I+]1)(I)I

| SMILES1_Comment = [[dimer (chemistry)|dimer]]

| StdInChI_Ref = {{stdinchicite|changed|chemspider}}

| StdInChI =

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

|Section2={{Chembox Properties

| Formula = {{math|size=100%|AlI₃}}, {{math|size=100%|AlI₃·6H₂O}} (hexahydrate)

| MolarMass = 407.695 g/mol (anhydrous) <br> 515.786 g/mol (hexahydrate)<ref name=b92/>

| Appearance = white (anhydrous) or yellow powder (hexahydrate)<ref name=b92/>

| Density = 3.98 g/cm³ (anhydrous)<ref name=b92>{{RubberBible92nd|page=4.45}}</ref> 2.63 g/cm³ (hexahydrate)<ref name="Perry2016">{{cite book|author=Perry, Dale L. |title=Handbook of Inorganic Compounds, Second Edition|url=https://books.google.com/books?id=SFD30BvPBhoC&pg=PA8|date=19 April 2016|publisher=CRC Press|isbn=978-1-4398-1462-8|page=8}}</ref>

| MeltingPtC = 188.28

| MeltingPt_notes = (anhydrous) <br> 185&nbsp;°C, decomposes (hexahydrate)<ref name=b92/><ref name="Perry2016"/>

| BoilingPtC = 382

| BoilingPt_notes = anhydrous, sublimes<ref name=b92/>

| Solubility = very soluble, partial hydrolysis

| Solvent = [[ethanol|alcohol]], [[diethyl ether|ether]]

| SolubleOther = soluble (hexahydrate)

}}

|Section3={{Chembox Structure

| Structure_ref =<ref name="TroyanovKrahl2004"/>

| CrystalStruct = [[Monoclinic]], [[Pearson symbol|''mP16'']]

| SpaceGroup = P2₁/c, No. 14

| Coordination =

| LattConst_a = 1.1958 nm

| UnitCellFormulas = 8

| LattConst_b = 0.6128 nm

| LattConst_c = 1.8307 nm

| LattConst_alpha = 90

| LattConst_beta = 90

| LattConst_gamma = 90

| MolShape =

| OrbitalHybridisation =

| Dipole =

}}

| Section4 = {{Chembox Thermochemistry

| Thermochemistry_ref =<ref name=b92/>

| HeatCapacity = 98.7 J/(mol·K)

| Entropy = 195.9 J/(mol·K)

| DeltaHf = -302.9 kJ/mol

| DeltaGf =

| DeltaHc =

'''Aluminium iodide''' is a [[chemical compound]] containing [[aluminium]] and [[iodine]]. Invariably, the name refers to a compound of the composition {{chem|Al|I|3}}, formed by the reaction of aluminium and iodine<ref>{{cite book|doi=10.1002/9780470132357.ch39|chapter=Aluminum Iodide|title=Inorganic Syntheses|volume=4|pages=117–119|year=1953|last1=Watt|first1=George W|last2=Hall|first2=James L|last3=Taylor|first3=William Lloyd|last4=Kleinberg|first4=Jacob|isbn=9780470132357}}</ref> or the action of [[Hydrogen iodide|{{chem|H|I}}]] on {{chem|Al}} metal. The hexahydrate is obtained from a reaction between metallic aluminum or [[aluminum hydroxide]] with [[hydrogen iodide]] or [[hydroiodic acid]]. Like the related chloride and bromide, {{chem|Al|I|3}} is a strong [[Lewis acids and bases|Lewis acid]] and will absorb water from the atmosphere. It is employed as a [[reagent]] for the scission of certain kinds of C-O and N-O bonds. It cleaves aryl [[diethyl ether|ether]]s and deoxygenates [[epoxide]]s.<ref>{{cite book| author = Gugelchuk, M. | chapter=Aluminum Iodide|title =Encyclopedia of Reagents for Organic Synthesis |editor=L. Paquette| year = 2004| publisher =J. Wiley & Sons| place = New York| doi = 10.1002/047084289X.ra083| isbn=0471936235}}</ref>

==Structure==

Solid {{chem|Al|I|3}} is dimeric, consisting of {{chem|Al|2|I|6}}, similar to that of [[aluminium tribromide|{{chem|Al|Br|3|}}]].<ref name="TroyanovKrahl2004">{{cite journal|last1=Troyanov|first1=Sergey I.|last2=Krahl|first2=Thoralf|last3=Kemnitz|first3=Erhard|title=Crystal structures of {{math|size=100%|1=GaX₃(X= Cl, Br, I)}} and {{math|size=100%|AlI₃}}|journal=Zeitschrift für Kristallographie|volume=219|issue=2–2004|year=2004|pages=88–92|doi=10.1524/zkri.219.2.88.26320|s2cid=101603507}}</ref> The structure of monomeric and dimeric forms have been characterized in the gas phase.<ref name="HargittaiRéffy2006">{{cite journal|last1=Hargittai|first1=Magdolna|last2=Réffy|first2=Balázs|last3=Kolonits|first3=Mária|title=An Intricate Molecule: Aluminum Triiodide. Molecular Structure of {{math|size=100%|AlI₃}}and {{math|size=100%|Al₂I₆}} from Electron Diffraction and Computation|journal=The Journal of Physical Chemistry A|volume=110|issue=10|year=2006|pages=3770–3777|doi=10.1021/jp056498e|pmid=16526661}}</ref> The monomer, {{chem|Al|I|3}}, is trigonal planar with a bond length of 2.448(6) Å, and the bridged dimer, {{chem|Al|2|I|6}}, at 430 K is a similar to [[Aluminium chloride|{{chem|Al|2|Cl|6}}]] and [[Aluminium bromide|{{chem|Al|2|Br|6}}]] with {{chem2|Al\sI}} bond lengths of 2.456(6) Å (terminal) and 2.670(8) Å (bridging). The dimer is described as floppy with an equilibrium geometry of D_2h.

{{main|Aluminium monoiodide}}

[[File:06. Директна синтеза на алуминиум јодид.webm|thumb|left|280px|Experiment showing a direct synthesis of aluminum iodide. Few drops of water are added to a homogenised mixture of aluminum powder and powdered iodine. After short time (an induction period) a vigorous reaction occurs followed by emission of intense colored vapors. The purple vapours are due to evaporation of iodine as a consequence of increased temperature of the system, and the brown ones are probably due to smoke of an adduct of the reaction product with excess of iodine. The exergonic reaction {{chem2|2Al(s) + 3I2(s) -> 2AlI3(s)}} is at the origin of the phenomenon observed.]]

The name "aluminium iodide" is widely assumed to describe the triiodide or its dimer. In fact, a monoiodide also enjoys a role in the Al–I system, although the compound AlI is unstable at room temperature relative to the triiodide:<ref>{{cite journal| title = Aluminum(I) and Gallium(I) Compounds: Syntheses, Structures, and Reactions|author1=Dohmeier, C. |author2=Loos, D. |author3=Schnöckel, H. | journal = Angewandte Chemie International Edition | year =1996| volume =35|issue=2 | pages =129–149| doi =10.1002/anie.199601291}}</ref>

:<chem>3AlI -> AlI3 + 2Al</chem>

An illustrative derivative of aluminium monoiodide is the cyclic [[adduct]] formed with [[triethylamine]], {{chem|Al|4|I|4|(NEt|3|)|4}}.

==External links==

*{{Commonscatinline}}

{{Iodides}}

{{Use dmy dates|date=March 2018}}

[[Category:Aluminium compounds|iodide]]