Cadmium sulfide

Cadmium Sulfide

Cadmium sulfide pigment

Cadmium sulfide (CdS) is a chemical compound that is a yellow solid. It is an important material in the field of semiconductors and is used in a variety of applications, including solar cells, photodetectors, and as a pigment in paints.

Chemical Properties

Cadmium sulfide is composed of cadmium and sulfur, with the chemical formula CdS. It is a binary compound and is known for its bright yellow color. CdS is insoluble in water but can be dissolved in acids. It has a melting point of 1750 °C and a density of 4.826 g/cm_.

Crystal Structure

CdS can exist in two different crystal structures: the wurtzite structure and the zinc blende structure. The wurtzite structure is hexagonal, while the zinc blende structure is cubic. The wurtzite form is more stable at room temperature.

Applications

Pigments

Cadmium sulfide is used as a pigment known as "cadmium yellow." It is valued for its bright color and stability. It is used in artists' paints, plastics, and ceramics.

Semiconductors

CdS is a direct bandgap semiconductor with a bandgap of about 2.42 eV at room temperature. This makes it suitable for use in photovoltaic cells and photodetectors. It is often used in thin-film solar cells, where it acts as a window layer that allows light to pass through to the active layer.

Photoconductors

Cadmium sulfide is also used in photoconductors, which are materials that become more conductive when exposed to light. This property is utilized in light sensors and photocopying machines.

Safety and Environmental Concerns

Cadmium compounds, including cadmium sulfide, are toxic and pose environmental and health risks. Exposure to cadmium can cause serious health problems, including kidney damage and bone disease. Therefore, the use of cadmium sulfide is regulated in many countries, and alternatives are often sought in applications where possible.

Related Pages

• Cadmium
• Sulfur
• Semiconductor
• Photovoltaic cell
• Pigment

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  Cadmium sulfide
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  Cadmiumgelb Pigment