I’m sorry, but there seems to be a mistake in your question. The compound “Al2S12” does not exist. You may have made a typo. The compound Al2S3 (Aluminium sulphide) is a white, odorless solid. This compound can be synthesized by reacting aluminium with sulphur, producing Al2S3 and releasing heat.
In terms of structure, each aluminium atom is bonded with six sulphur atoms to form a cube. The molar mass of Al2S3 is 150.158 g/mol.
In a reaction with water, Al2S3 produces sulphur and aluminium hydroxide which is a strong acid.
Al2S3 + 6H2O -> 3H2S + 2Al(OH)3
In a reaction with acid, Al2S3 also produces sulphur and aluminium ions.
I hope this information can help you. Please check the chemical formula you wish to study and ask your question again.