Aluminum sulfide or aluminum sulfide is a chemical compound with the formula Al2S3 . This colorless species has an interesting structural chemical, which exists in many forms. The material is sensitive to moisture, hydrolyzing to hydrated aluminum oxide/hydroxide.  It can be triggered when the sulfide is exposed to the atmosphere. The hydrolysis reaction generates gaseous hydrogen sulfide (H2S).
chemical formula= al 2 s 3
molar mass =150.158 g/mol
appearance gray =solid
density =2.02 g / cm3
Melting point =1,100 °C (2,010 °F; 1,370 K)
boiling point =1,500 °C (2,730 °F; 1,770 K) excellent
Solubility in water =disintegrates
solubility =insoluble in acetone
More than six crystalline forms of aluminum sulfide are known and only a few are listed below. Most of them have similar, wurtzite -like structures, and differ by arrangement of lattice vacancies, which form ordered or disordered subdivisions.
|a (a)||CA)||(g / cm3 )|
|b||hexagonal||P6 3 MC||3.579||५.८२९||२.४९५|
|d||square||I4 1 / amd||७.०२६||29.819||2.71|
The β and phases are obtained by annealing the most stable α-Al 2S 3 phase at several hundred °C .  Compressing aluminum sulfide to 2–65 kbar leads to a phase where the vacancies are arranged in a superlattice of tetragonal symmetry. 
Unlike Al 2 O 3 , in which the Al(III) centers occupy octahedral pores, the more extended structure of Al 2 S 3 stabilizes the Al(III) centers in one-third of the tetrahedral pores of the hexagonal close-packed arrangement sulfide ions. At higher temperatures, the Al(III) centers randomize to give the “defect wurtzite ” structure. and still at high temperatures stabilize -Al 2 S 3 forms, with a structure similar to -Al2O3 .
The molecular derivatives of Al 2S 3 are not known . Mixed Al–S–Cl compounds are however known. Al 2 to 3 and Al 2 to 3 are also known.
Aluminum sulfide is readily prepared by ignition of the elements 
2Al + 3S → Al 2S 3
This reaction is extremely exothermic and it is not necessary or desirable to heat the entire mass of the sulphur-aluminum mixture; (except for potentially very small amounts of reactants). The product will be made in a fused form; It reaches temperatures in excess of 1100 °C and can melt its way through steel. Cold product is very hard.