Arsenic

Uses

Arsenic’s most significant modern application is in the compound gallium arsenide, a semiconductor that moves electrons faster than silicon and is used in LEDs, laser diodes, solar cells for satellites, and high-frequency components in smartphones and other wireless devices. Lead alloyed with a small amount of arsenic is harder and holds its shape better, which is why it has long been used in things like ammunition and certain bearings.

Historically, arsenic compounds played a much broader role: vivid green pigments like Paris Green colored fabrics, wallpaper and paint for decades before their toxicity became widely understood, and arsenic-based wood preservatives were used to protect lumber from rot and insects, though many of these applications have since been phased out or heavily restricted as their health risks became clear.

History

Unlike most elements, arsenic has no single discoverer — its compounds were recognized and deliberately used by civilizations in Egypt, Greece and China thousands of years ago, both for coloring and, notoriously, for poisoning. The medieval alchemist Albertus Magnus is often credited with being among the first to isolate arsenic in something close to its pure elemental form, around the 13th century, though records from that era are far from precise. Arsenic’s name likely traces back through Latin and Greek to a Persian or Syriac word associated with yellow pigment, reflecting its long use in dyes well before it was understood as a distinct chemical element.