sentence: Selenium is used in photocells.
sentences_after: The gray metallic form is used, as it changes its electrical conductivity when light shines on it. Selenium is also used as a catalyst. The largest use is to color glass red. It can be used in special brasses instead of lead. It is used in some rectifiers.
concept_name: selenium
headings: Selenium Uses In materials
categories: Chemical elements Nonmetals