arsenic ar·se·nic (är'sə-nĭk)
A poisonous metallic element having three allotropes, of which the gray form is the most common. Arsenic compounds are used in insecticides and solid-state doping agents. Atomic number 33; atomic weight 74.922; valence 3, 5. Gray arsenic melts at 817°C (at 28 atm pressure), sublimes at 614°C, and has a specific gravity of 5.73. adj. ar·sen·ic (är-sěn'ĭk)
Of or containing arsenic, especially with valence 5.