Aluminium iodide

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Aluminium iodide
Aluminium-iodide-3D-balls.png
Jodid hlinity.PNG
Names
Preferred IUPAC name
Aluminium iodide
Other names
Aluminium(III) iodide

Aluminum iodide
Aluminium triiodide

Aluminum triiodide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.029.140 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 232-054-8
PubChem CID
UNII
UN number UN 3260
  • Key: CECABOMBVQNBEC-UHFFFAOYSA-K Yes check.svgY
  • Key: CECABOMBVQNBEC-DFZHHIFOAE
  • I[Al](I)I
  • dimer:I[Al-]1(I)[I+][Al-]([I+]1)(I)I
Properties
AlI3, AlI3·6H2O (hexahydrate)
Molar mass 407.695 g/mol (anhydrous)
515.786 g/mol (hexahydrate) [1]
Appearancewhite (anhydrous) or yellow powder (hexahydrate) [1]
Density 3.98 g/cm3 (anhydrous) [1] 2.63 g/cm3 (hexahydrate) [2]
Melting point 188.28 °C (370.90 °F; 461.43 K) (anhydrous)
185 °C, decomposes (hexahydrate) [1] [2]
Boiling point 382 °C (720 °F; 655 K) anhydrous, sublimes [1]
very soluble, partial hydrolysis
Solubility in alcohol, ether soluble (hexahydrate)
Structure [3]
Monoclinic, mP16
P21/c, No. 14
a = 1.1958 nm, b = 0.6128 nm, c = 1.8307 nm
α = 90°, β = 90°, γ = 90°
8
Thermochemistry [1]
98.7 J/(mol·K)
Std molar
entropy (S⦵298)
195.9 J/(mol·K)
-302.9 kJ/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Aluminium iodide is a chemical compound containing aluminium and iodine. Invariably, the name refers to a compound of the composition AlI
3, formed by the reaction of aluminium and iodine [4] or the action of HI on 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, AlI
3 is a strong 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 ethers and deoxygenates epoxides. [5]

Contents

Structure

Solid AlI
3 is dimeric, consisting of Al
2I
6, similar to that of AlBr
3. [3] The structure of monomeric and dimeric forms have been characterized in the gas phase. [6] The monomer, AlI
3, is trigonal planar with a bond length of 2.448(6) Å, and the bridged dimer, Al
2I
6, at 430 K is a similar to Al
2Cl
6 and Al
2Br
6 with Al−I 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 D2h.

Aluminium(I) iodide

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 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: [7]

An illustrative derivative of aluminium monoiodide is the cyclic adduct formed with triethylamine, Al
4I
4(NEt
3)
4.

Related Research Articles

<span class="mw-page-title-main">Aluminium chloride</span> Chemical compound

Aluminium chloride, also known as aluminium trichloride, is an inorganic compound with the formula AlCl3. It forms a hexahydrate with the formula [Al(H2O)6]Cl3, containing six water molecules of hydration. Both the anhydrous form and the hexahydrate are colourless crystals, but samples are often contaminated with iron(III) chloride, giving them a yellow colour.

<span class="mw-page-title-main">Trimethylaluminium</span> Chemical compound

Trimethylaluminium is one of the simplest examples of an organoaluminium compound. Despite its name it has the formula Al2(CH3)6 (abbreviated as Al2Me6 or TMA), as it exists as a dimer. This colorless liquid is pyrophoric. It is an industrially important compound, closely related to triethylaluminium.

<span class="mw-page-title-main">Aluminium bromide</span> Chemical compound

Aluminium bromide is any chemical compound with the empirical formula AlBrx. Aluminium tribromide is the most common form of aluminium bromide. It is a colorless, sublimable hygroscopic solid; hence old samples tend to be hydrated, mostly as aluminium tribromide hexahydrate (AlBr3·6H2O).

<span class="mw-page-title-main">Triiodide</span> Ion

In chemistry, triiodide usually refers to the triiodide ion, I−
3. This anion, one of the polyhalogen ions, is composed of three iodine atoms. It is formed by combining aqueous solutions of iodide salts and iodine. Some salts of the anion have been isolated, including thallium(I) triiodide (Tl+[I3]−) and ammonium triiodide ([NH4]+[I3]−). Triiodide is observed to be a red colour in solution.

<span class="mw-page-title-main">Aluminium isopropoxide</span> Chemical compound

Aluminium isopropoxide is the chemical compound usually described with the formula Al(O-i-Pr)3, where i-Pr is the isopropyl group (–CH(CH3)2). This colourless solid is a useful reagent in organic synthesis.

<span class="mw-page-title-main">Gallium(III) iodide</span> Chemical compound

Gallium(III) iodide is the inorganic compound with the formula GaI3. A yellow hygroscopic solid, it is the most common iodide of gallium. In the chemical vapor transport method of growing crystals of gallium arsenide uses iodine as the transport agent. In the solid state, it exists as the dimer Ga2I6. When vaporized, its forms GaI3 molecules of D3h symmetry where the Ga–I distance is 2.458 Angstroms.

Iodine compounds are compounds containing the element iodine. Iodine can form compounds using multiple oxidation states. Iodine is quite reactive, but it is much less reactive than the other halogens. For example, while chlorine gas will halogenate carbon monoxide, nitric oxide, and sulfur dioxide, iodine will not do so. Furthermore, iodination of metals tends to result in lower oxidation states than chlorination or bromination; for example, rhenium metal reacts with chlorine to form rhenium hexachloride, but with bromine it forms only rhenium pentabromide and iodine can achieve only rhenium tetraiodide. By the same token, however, since iodine has the lowest ionisation energy among the halogens and is the most easily oxidised of them, it has a more significant cationic chemistry and its higher oxidation states are rather more stable than those of bromine and chlorine, for example in iodine heptafluoride.

<span class="mw-page-title-main">Bismuth(III) iodide</span> Chemical compound

Bismuth(III) iodide is the inorganic compound with the formula BiI3. This gray-black salt is the product of the reaction of bismuth and iodine, which once was of interest in qualitative inorganic analysis.

<span class="mw-page-title-main">Arsenic triiodide</span> Chemical compound

Arsenic triiodide is the inorganic compound with the formula AsI3. It is an orange to dark red solid that readily sublimes. It is a pyramidal molecule that is useful for preparing organoarsenic compounds.

<span class="mw-page-title-main">Trimethylsilyl iodide</span> Chemical compound

Trimethylsilyl iodide (iodotrimethylsilane or TMSI) is an organosilicon compound with the chemical formula (CH3)3SiI. It is a colorless, volatile liquid at room temperature.

<span class="mw-page-title-main">Chromium(III) iodide</span> Chemical compound

Chromium(III) iodide, also known as chromium triiodide, is an inorganic compound with the formula CrI3. It is a black solid that is used to prepare other chromium iodides.

Cerium(III) iodide (CeI3) is the compound formed by cerium(III) cations and iodide anions.

Gallium monoiodide is an inorganic gallium compound with the formula GaI or Ga4I4. It is a pale green solid and mixed valent gallium compound, which can contain gallium in the 0, +1, +2, and +3 oxidation states. It is used as a pathway for many gallium-based products. Unlike the gallium(I) halides first crystallographically characterized, gallium monoiodide has a more facile synthesis allowing a synthetic route to many low-valent gallium compounds.

<span class="mw-page-title-main">Indium(III) iodide</span> Chemical compound

Indium(III) iodide or indium triiodide is a chemical compound of indium and iodine with the formula InI3.

<span class="mw-page-title-main">Praseodymium(III) iodide</span> Chemical compound

Praseodymium(III) iodide is an inorganic salt, consisting of the rare-earth metal praseodymium and iodine, with the chemical formula PrI3. It forms green crystals. It is soluble in water.

<span class="mw-page-title-main">Zirconium(III) iodide</span> Chemical compound

Zirconium(III) iodide is an inorganic compound with the formula ZrI3.

<span class="mw-page-title-main">Lanthanum(III) iodide</span> Chemical compound

Lanthanum(III) iodide is an inorganic compound containing lanthanum and iodine with the chemical formula LaI
3.

Europium(III) iodide is an inorganic compound containing europium and iodine with the chemical formula EuI3.

<span class="mw-page-title-main">Lutetium(III) iodide</span> Chemical compound

Lutetium(III) iodide or lutetium iodide is an inorganic compound consisting of iodine and lutetium, with the chemical formula of LuI3.

<span class="mw-page-title-main">Hafnium(III) iodide</span> Chemical compound

Hafnium(III) iodide is an inorganic compound of hafnium and iodine with the formula Hf I3. It is a black solid.

References

  1. 1 2 3 4 5 6 Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, FL: CRC Press. p. 4.45. ISBN   1-4398-5511-0.
  2. 1 2 Perry, Dale L. (19 April 2016). Handbook of Inorganic Compounds, Second Edition. CRC Press. p. 8. ISBN   978-1-4398-1462-8.
  3. 1 2 Troyanov, Sergey I.; Krahl, Thoralf; Kemnitz, Erhard (2004). "Crystal structures of GaX3(X= Cl, Br, I) and AlI3". Zeitschrift für Kristallographie. 219 (2–2004): 88–92. doi:10.1524/zkri.219.2.88.26320. S2CID   101603507.
  4. ↑ Watt, George W; Hall, James L; Taylor, William Lloyd; Kleinberg, Jacob (1953). "Aluminum Iodide". Inorganic Syntheses. Vol. 4. pp. 117–119. doi:10.1002/9780470132357.ch39. ISBN   9780470132357.
  5. ↑ Gugelchuk, M. (2004). "Aluminum Iodide". In L. Paquette (ed.). Encyclopedia of Reagents for Organic Synthesis. New York: J. Wiley & Sons. doi:10.1002/047084289X.ra083. ISBN   0471936235.
  6. ↑ Hargittai, Magdolna; Réffy, Balázs; Kolonits, Mária (2006). "An Intricate Molecule: Aluminum Triiodide. Molecular Structure of AlI3and Al2I6 from Electron Diffraction and Computation". The Journal of Physical Chemistry A. 110 (10): 3770–3777. doi:10.1021/jp056498e. PMID   16526661.
  7. ↑ Dohmeier, C.; Loos, D.; Schnöckel, H. (1996). "Aluminum(I) and Gallium(I) Compounds: Syntheses, Structures, and Reactions". Angewandte Chemie International Edition. 35 (2): 129–149. doi:10.1002/anie.199601291.

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