Arsenic occurs in many minerals, usually in combination with sulfur and metals.
Core Principles & Analysis
Arsenic compounds were known to ancient metallurgists, and isolation of the element is traditionally credited to Albertus Magnus around 1250.
The gray metalloid sublimes directly to vapor at atmospheric pressure, and its tasteless, poisonous oxide was the notorious 'inheritance powder' until the 1836 Marsh test made it forensically detectable.
Arsenic is alloyed into gallium arsenide semiconductors for high-speed electronics and hardens the lead grids of car batteries, while former uses in pesticides and treated lumber have been phased out.