Arsenic is often used as a doping agent for solid-state devices. Gallium arsenide is used in lasers that convert electricity into coherent light.
Arsenic compounds, such as Paris green, calcium arsenate and lead arsenate, are used as insecticides and in other poisons.
Arsenic is used in pyrotechnics to give additional color to the flame. Arsenic improves the sphericity of lead shot.
Arsenic has been used as a poison in history but is easily detectable. To detect arsenic, scientists may use Marsh's test. Named after British chemist James Marsh, the test identifies the presence of arsenic in the field of forensic toxicology.