Arsenic is a chemical element, its name is called arsenic, the element symbol is As, the atomic number, that is, the number of protons in the nucleus or the number of nuclear charges is 33, the relative atomic mass is 74.92, in the Periodic Table of the Elements is in the fourth cycle, the fifth main group, belongs to the non-metallic elements.

Arsenic monomers have yellow, gray, black and brown isomers. Gray crystals are the most common form of monomers, brittle and hard, with a metallic luster (so arsenic monomers are also known as metallic arsenic), easy to conduct heat and electricity, easy to be pounded into powder. It is non-toxic.

But arsenic oxide is highly toxic ---- arsenic trioxide commonly known as arsenic.