aluminium telluride
{{Short description|Inorganic compound}}
{{Chembox
| Name = Aluminium telluride
| Reference =
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| OtherNames = μ-Telluride(ditelluroxo)dialuminium, Dialuminium tritelluride, Aluminium (III) telluride
|Section1={{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 22797847
| EC_number = 234-939-4
| DTXSID = DTXSID601014260
| InChI = 1S/2Al.3Te/q2*+3;3*-2
| InChIKey = IBHHFWUKPAWXSJ-UHFFFAOYSA-N
| SMILES = [Te]=[Al][Te][Al]=[Te]
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = InChI=1S/2Al.3Te
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = RETRTUZSQWNRQG-UHFFFAOYSA-N
| CASNo_Ref = {{cascite|correct|??}}
| CASNo = 12043-29-7
| PubChem = 12674524
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|Section2={{Chembox Properties
| Formula = Al2Te3
| MolarMass = 436.76 g/mol
| Appearance = dark grey to black solid
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| Solubility = decomposes
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|Section3={{Chembox Structure
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|Section4={{Chembox Thermochemistry
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Aluminium telluride is an inorganic chemical compound of aluminium and tellurium with the chemical formula Al2Te3.
Preparation
Aluminium telluride can be obtained by direct combination of aluminium metal with elemental tellurium at {{convert|1000|C|K F}}.{{cite book| author=Dale L. Perry | title=Handbook of Inorganic Compounds | publisher=CRC Press | year=2016 | isbn=978-1-4398-1462-8 | via=Google Books|url=https://books.google.com/books?id=SFD30BvPBhoC&pg=PA488|access-date=2024-07-28|url-access=limited}}
: {{chem2|2 Al + 3 Te -> Al2Te3}}
Properties
Aluminium telluride is a very air-sensitive dark grey to black solid. It has a band gap of 2.4 eV.{{cite book|first1=Stepan S.|last1=Batsanov|first2=Andrei S.|last2=Batsanov | title=Introduction to Structural Chemistry | publisher=Springer Netherlands | year=2012 | isbn=978-94-007-4771-5 | page=130 | url=https://books.google.com/books?id=YiHHkIA7K4MC&pg=PA130|via=Google Books|access-date=2024-07-17}} The compound decomposes in humid air.{{cite book| first=Georg | last=Brauer | title=Handbook of Preparative Inorganic Chemistry V1 | date=2 December 2012 | publisher=Elsevier Science | isbn=978-0-323-16127-5 |page=826 | url=https://books.google.com/books?id=kaa2qeFRXmUC&pg=PA826|via=Google Books|access-date=2024-07-17}}
In its pure form, it occurs in at least two phases. The orange-red low-temperature (α) modification transforms into the yellow high-temperature (β) form at {{convert|720|C|K F}}. The conversion from β- to α-Al2Te3, which is associated with such a small enthalpy change that it cannot be observed with differential thermal analysis, takes place after prolonged annealing just below the conversion point. The α form crystallizes in the monoclinic crystal system with the lattice constants a = 13.885 Å, b = 7.189 Å, c = 4.246 Å, p = 90.21° and an additional superstructure. The β form has a monoclinic crystal structure with space group P21/c and the lattice constants a = 7.181(1) Å, b = 12.848(3) Å, c = 14.167(3) Å, and b= 90.04(2)°. This form represents a separate structure type. The tellurium atoms form a hexagonal dense packing parallel to the (001) plane; one-third of the tetrahedral vacancies are occupied by aluminium atoms, whereby the tetrahedral vacancies are occupied in such a way that a layered structure is formed. Some sources also report another form of the defect wurtzite type.{{cite journal|last1=Conrad|first1=O|last2=Schiemann|first2=A|last3=Krebs |first3=B|year=1997|title=Die Kristallstruktur von β-Al2Te3|trans-title=The Crystal Structure of β-Al2Te3|lang=de|journal=Zeitschrift für anorganische und allgemeine Chemie|volume=623|pages=1006–1010|doi=10.1002/zaac.199762301157| url=https://onlinelibrary.wiley.com/doi/epdf/10.1002/zaac.199762301157|url-access=subscription}}
Uses
Aluminium telluride is used in the semiconductor industry. It can also be used to produce hydrogen telluride by reacting with hydrogen chloride.{{cite book| first1=Erwin |last1=Riedel|first2=Christoph|last2=Janiak | title=Anorganische Chemie | publisher=De Gruyter | year=2022 | isbn= 978-3-11-069458-1| pages= | url=https://books.google.com/books?id=aXdWEAAAQBAJ | via=Google Books}}
: {{chem2|Al2Te3 + 6 HCl -> 3 H2Te + 2 AlCl3}}