Thallium

Definition

Thallium is a chemical constituent with the symbol Tl and atomic number 81. This soft gray malleable poor metal resembles tin but discolors when exposed to air. Roughly 60-70% of thallium manufacture is used in the electronics industry, and the rest is used in the pharmaceutical industry and in glass manufacturing.

Application

Thallium(I) sulfide's electrical conductivity change with exposure to infrared light so making this compound useful in photocells