Arsenic is a semi-metal, as it shows both metallic and non-metallic properties depending on the modification. Arsenic exists in various modifications: metallic gray, yellow or black arsenic and mostly occurs in the form of sulphides. The main use of metallic arsenic is as an alloying component for lead and copper alloys. Adding Arsenic significantly increases the hardness of the alloys. In semiconductor technology, high-purity arsenic is used for doping silicon and germanium and for producing intermetallic compounds with aluminum, gallium and indium. Furthermore, the electronics industry uses arsenic to manufacture high-frequency components such as integrated circuits (ICs), light-emitting diodes (LEDs) and laser diodes (LDs). Arsenic compounds are also used to make paints, in glass production to clarify the flow of glass and to preserve animal and vegetable matter.