Silver Sulfide (Ag2S) Semiconductors

Topics Covered

Chemical Properties
Thermal, Mechanical and Optical Properties
Safety Information


Silver sulfide is a dense black solid that is insoluble in all solvents, but is degraded by strong acids. It features a covalent bond, as it is made up of silver and sulfur. When silver sulfide is formed on electrical contacts operating at atmosphere rich in hydrogen sulfide, it results to the formation of long filaments known as silver whiskers. It is found in nature as relatively low temperature mineral acanthite.


Silver sulfide finds applications in the following:

  • Photosensitizer in photography
  • Anti-bacterial and anti-microbial agents
  • Laboratory reagents.

Chemical Properties

The chemical properties of silver sulfide are provided in the table below:

Chemical Properties
Chemical Formula Ag2S
Molecular Weight 247.8
CAS No. 21548-73-2
Group Silver – 11
Sulfur - 16
Crystal Structure Orthogonal
Lattice Constant a = 4.228 Å
b = 6.928 Å
c = 7.862 Å

Electrical Properties

The electrical properties of silver sulfide are provided in the table below:

Electrical Properties
Dielectric Constant 6
Band Gap 1.08 eV

Thermal, Mechanical and Optical Properties

The thermal, mechanical and optical properties of silver sulfide are provided in the tables below:

Thermal Properties
Heat of Fusion 56.9 J/g
Heat of Formation -32.6 kJ/mol
Mechanical Properties
Density 7.23 g/cm3
Melting Point 825°C
Mohs Hardness 2.3
Optical Properties
Refractive Index 2.2

Safety Information

Safety Information
Risk Phrases R36 - Irritating to eyes
R37 - Irritating to respiratory system
R38 - Irritating to skin.
Safety Phrases S 24 - Avoid contact with skin
S 26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice
S 36 - Wear suitable protective clothing.

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