sulfidecadmium

Sulfidecadmium, more commonly called cadmium sulfide (CdS), is an inorganic compound that forms yellow to orange solids. It occurs in nature as the mineral greenockite, typically in hydrothermal veins or in zinc-rich ore deposits.

CdS crystallizes in two primary forms, cubic zinc blende and hexagonal wurtzite. It has a direct bandgap of about 2.4 eV at room temperature, making it a wide-bandgap semiconductor. The visible-edge absorption gives bulk CdS its characteristic yellow color; nanoscale forms exhibit size-dependent optical properties.

Applications for CdS include use as a pigment (cadmium yellow) and as a semiconductor material in optoelectronic devices. It is widely employed as a n-type window layer in CdTe solar cells and in photodetectors and quantum-dot technologies. Doping and nanostructuring can modify its electronic and optical properties for specific applications.

Synthesis typically involves precipitation of sulfide from cadmium salts or sulfidation of cadmium-containing precursors; hydrothermal methods are also used. CdS is relatively insoluble in water, but cadmium compounds are toxic and require proper handling and disposal under regulatory guidelines.

In nature, the mineral greenockite is usually found with sulfide ore deposits and can occur as crystals or as crusts with varying shades of pale to brownish yellow.