Aluminum Sulfide
- Aluminum Sulfide Identification
- How is Aluminum Sulfide Prepared
- Reactions with Other Compounds
- Properties and Characteristics of Aluminum Sulfide
- What is It Used for
- Is Aluminum Sulfide Toxic
Aluminum sulfide, also called dialuminium trisulfide, is an ionic compound of aluminum and sulfur represented by the chemical formula Al2S3 [1, 2]. It exists in different crystalline forms and hydrolyzes to aluminum hydroxide/oxide [3, 4].
Aluminum Sulfide Identification |
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CAS Number | 1302-81-4 [1, 2] |
PubChem CID | 16684788 [6] |
ChemSpider ID | 140154 [1] |
EC Number | 215-109-0 [1, 2] |
InChI Key | ZPXDOGRYMSWBBM-UHFFFAOYSA-N [6] |

Aluminum Sulfide Formula
How is Aluminum Sulfide Prepared
Its synthesis through direct heating of aluminum and sulfur can be represented by the following equation [7]:
2Al 3S → Al2S3
However, the reaction is highly exothermic, and it is not desirable to heat the entire mixture [7]. Also, sulfur is a volatile reactant that melts away before the reaction takes place [7]. Therefore, lead sulfide is often used for the preparation of Al2S3 [7]:
2Al 3PbS → Al2S3 3Pb

Aluminum Sulfide
Reactions with Other Compounds
Aluminum Sulfide and Water
When aluminum sulfide is exposed to moisture in the atmosphere, it undergoes hydrolysis reaction to form aluminum hydroxide and hydrogen sulfide [5].
Al2S3 6H2O → 2Al(OH)3 3H2S
Aluminum Sulfide and Hydrochloric Acid
Aluminum sulfide upon reacting with hydrochloric acid forms hydrogen sulfide and aluminum chloride, as shown below [8]:
Al2S3 6HCl → 2AlCl3 3H2S

Aluminum Sulfide Lewis Structure
Properties and Characteristics of Aluminum Sulfide
General Properties |
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Molar Mass/Molecular Weight | 150.158 g/mol [1] |
Physical Properties |
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Color and Appearance | Gray powder or granules [2] |
Melting Point | 1,100 °C, 2,012 °F [2] |
Boiling Point | 1,500 °C, 2,732 °F [2] |
Density | 2.32 g cm-3 [2] |
State of matter at room temperature (solid/liquid/gas) | Solid [2] |
Solubility | Insoluble in (CH3)2CO (acetone) [9] |
Solubility in Water | Reacts and decomposes in H2O [9] |
Heat Capacity (C) | 105.1 J/mol K |
Standard Molar Enthalpy | -724 kJ/mol [9] |
Standard Molar Entropy | 116.9 J/mol K |
Atomic Properties |
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Crystal Structure | Trigonal, tetragonal, hexagonal [3, 4] |

Aluminum Sulfide Crystal Structure
What is It Used for
- Producing organic compounds like ethanethiol and chemicals required for tanning and making paper [10]
- Manufacturing cathodes used in lithium-sulfur solid-state batteries [11]
- Preparing hydrogen sulfide that has several industrial uses [11]
Is Aluminum Sulfide Toxic
Exposure to aluminum sulfide can cause skin and severe eye irritation [12]. Inhalation of dust, vapor, or fumes can cause difficulty in breathing [12].
References:
- Aluminum Sulfide (2:3) – Chemspider.com
- Aluminum Sulfide – Americanelements.com
- Synthesis and Crystal Structure of a Novel Hexagonal Modification of Al2S3 with Five-coordinated Aluminum – Onlinelibrary.wiley.com
- High-pressure Spinel Type Al2S3 and MnAl2S4 – Adsabs.harvard.edu
- Aluminum Sulfide React with Water – Chemiday.com
- ZPXDOGRYMSWBBM-UHFFFAOYSA-N – Pubchem.ncbi.nlm.nih.gov
- Preparation of Aluminum Sulfide – Prepchem.com
- Aluminum Sulfide React with Hydrogen – Chemiday.com
- Aluminum Sulfide [Al2S3] – Periodic-table-of-elements.org
- What Are the Uses of Aluminum Sulfide? – Reference.com
- Aluminum Sulfide – Chemicalbook.com
- Safety Data Sheet Aluminum Sulfide – Ltschem.com