Sulfur d'alumini

De Viquipèdia

Aquesta pàgina està traduint-se de l'idioma anglès a partir de l'article Aluminum sulfide, raó per la qual pot haver-hi llacunes de continguts, errors sintàctics o escrits sense traduir.
Podeu col·laborar amb la Viquipèdia continuant amb la traducció des de l'article original. Si l'article roman sense traducció completa durant molt de temps, podrà passar al registre de pàgines per esborrar.

Sulfur d'alumini

[[Imatge:|200px]]

General

Altres noms

Fórmula molecular

Al₂S₃

Massa molar

150.158076 g/mol g/mol

Aspecte

Incolor

Número CAS

[1302-81-4]

Propietats

2.0 g/cm³, sòlid

soluble

1100°C

1500°C (sublima)

Estructura

Geometria
de coordinació

Estructura cristal·lina

Perills

MSDS

MSDS externa

Perills

Punt d'inflamabilitat

No inflamable

Si no s'indica el contrari, les dades són pels materials
en condicions estàndard (25 °C, 100 kPa)
Avís d'exempció de responsabilitat

Aluminium sulfide is the name for the chemical compound with the formula Al₂S₃. 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.^[1] The hydrolysis reaction also generates the odoriferous and toxic gas hydrogen sulfide (H₂S).

Unlike Al₂O₃, in which the Al(III) centers occupy octahedral holes, the more expanded framework of Al₂S₃ 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-Al₂S₃ forms, with a structure akin to γ-Al₂O₃.

Molecular derivatives of Al₂S₃ are not known. Mixed Al-S-Cl compounds are however known. Also Al₂Se₃ and Al₂Te₃ are also known.

[edita] Preparació

Aluminium sulfide is readily prepared by ignition of the elements:

2Al + 3S → Al₂S₃

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.