Xerox copiers
solar cells

Selenium exists in several solid allotropic forms with colors varying from the dark-red to the black, being the hexagonal crystalline form the more stable under normal conditions. In this form, selenium has properties of a typical semiconductor but its more important electronic property is photocondutivity. For this reason it is mostly used in producing photocells, rectifiers and photographic exposure meters.

Besides these applications, selenium and its compounds can be used in the processes of xerographic reproduction, in the glass industry (cadmium seleniate, to produce red-ruby color), as degasifier in the metallurgical industry, as vulcanizing agent, as oxidizer in some reactions and as catalyst.