Aluminium sulfide
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2008-05-31T18:23:05Z
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{{Chembox new
| Name = Aluminium sulfide
| OtherNames =
| Section1 = {{Chembox Identifiers
| CASNo = 1302-81-4
}}
| Section2 = {{Chembox Properties
| Formula = Al<sub>2</sub>S<sub>3</sub>
| MolarMass = 150.158076 g/mol
| Appearance = colorless
| Density = 2.0 g/cm<sup>3</sup>, solid
| Solubility = decomposes
| Solvent = other solvents
| SolubleOther = none
| MeltingPt = 1100°C
| BoilingPt = 1500°C (sublimes)
}}
| Section7 = {{Chembox Hazards
| EUClass = not listed
| NFPA-H = 4
| NFPA-R = 2
| NFPA-F = 0
}}
}}
'''Aluminium sulfide''' is the name for the [[chemical compound]] with the formula [[Aluminium|Al<sub>2</sub>]][[Sulfur|S<sub>3</sub>]]. This colorless species has an interesting structural chemistry, existing in three different forms. The material is sensitive to moisture, hydrolyzing readily to hydrated aluminium oxides/hydroxides.<ref>Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.</ref> The hydrolysis reaction also generates the odoriferous and toxic gas hydrogen sulfide (H<sub>2</sub>S).
Unlike Al<sub>2</sub>O<sub>3</sub>, in which the Al(III) centers occupy octahedral holes, the more expanded framework of Al<sub>2</sub>S<sub>3</sub> stabilizes the Al(III) centers into one third of the tetrahedral holes of a hexagonally close-packed arrangement of the sulfide anions. At higher temperature, the Al(III) centers become randomized to give a "defect [[wurtzite]]" structure. And at still higher temperatures stabilize the γ-Al<sub>2</sub>S<sub>3</sub> forms, with a structure akin to γ-Al<sub>2</sub>O<sub>3</sub>.
Molecular derivatives of Al<sub>2</sub>S<sub>3</sub> are not known. Mixed Al-S-Cl compounds are however known. Also Al<sub>2</sub>Se<sub>3</sub> and Al<sub>2</sub>Te<sub>3</sub> are also known.
==Preparation==
Aluminium sulfide is readily prepared by ignition of the elements:
:2Al + 3S → Al<sub>2</sub>S<sub>3</sub>
This reaction is extremely exothermic and it is not necessary or desirable to heat the whole mass of the sulfur-aluminium mixture; (except possibly for very small preps). The product will be created in a fused form; that is at greater than 1100°C and may melt its way through steel. The cooled product is very hard.
==References==
<references/>
MSDS: http://www.espi-metals.com/msds's/Aluminum%20Sulfide.htm
[[Category:Sulfides]]
[[Category:Aluminium compounds]]
{{inorganic-compound-stub}}
[[ar:كبريتيد ألومنيوم]]
[[ca:Sulfur d'alumini]]