Cadmium selenide, with the chemical formula CdSe, is a chemical compound composed of cadmium (Cd) and selenium (Se) atoms. It is a binary compound and belongs to the group of metal chalcogenides.

Here are some key points about cadmium selenide:

1. Structure: Cadmium selenide has a crystal structure where one cadmium (Cd) atom is bonded to one selenium (Se) atom in the form of CdSe.
2. Physical Properties: Cadmium selenide is a dark-colored solid at room temperature. It can exist in different crystal structures, including hexagonal and cubic forms.
3. Preparation: Cadmium selenide can be prepared by various methods, such as chemical vapor deposition (CVD), sputtering, and precipitation reactions.
4. Semiconductor Properties: Cadmium selenide is a semiconductor material with a direct bandgap, which means it efficiently absorbs and emits light. It is widely used in optoelectronic devices, such as light-emitting diodes (LEDs), photodetectors, and solar cells.
5. Uses: Cadmium selenide has numerous practical applications, particularly in the electronics and photonics industries, due to its semiconducting properties and light-emitting capabilities.
6. Toxicity: Cadmium and its compounds, including cadmium selenide, are toxic and can pose health hazards if ingested, inhaled, or come into contact with skin or eyes. Proper safety precautions and handling procedures should be followed when working with this compound.
7. Environmental Concerns: Cadmium and its compounds are also known to be harmful to the environment, and their release into the environment should be avoided.

Cadmium selenide is a valuable material in the field of optoelectronics due to its semiconductor properties and light-emitting capabilities. It finds applications in various devices that utilize light, such as LEDs, solar cells, and photodetectors. However, its toxicity requires careful handling and containment to ensure the safety of those working with the compound. As with any toxic substance, appropriate safety measures should be observed to prevent unnecessary exposure and potential hazards. Additionally, the proper disposal and recycling of cadmium-containing materials are essential to prevent environmental contamination.