The element Arsenic was name for the Greek word assenikos, which means male. It was discovered in 1250. Its use through the ages was mostly as a rat poison and also a nerve gas. It is not a metal, as it is classified as a semi-metal, but it behaves as a metal and evaporates in air. Atomic Number is 33. Its Atomic Weight is 74.92160. Its melting point is 1090 K (817C or 1503F). its density is 5.776 grams per cubic centimeter. Arsenic boils at 887 K (614C or 1137F) and is a solid at room temperature.
The boiling point for arsenic is lower than its melting point. This is because the measurements taken for the two points are taken at different atmospheric pressures. Arsenic changes to a gas from a solid, called sublimation, at 877 degrees K. to form liquid arsenic, the pressure must be higher. When the pressure is twenty eight times the standard, arsenic will melt at 1090 degrees K. if you measure arsenic at 28 times atmospheric pressure, the boiling point is higher than the melting point.
Arsenic was mined in compound form by the ancient civilizations in China, Greece, and Egypt, but it was first isolated in 1250 by a German chemist named Albertus Magnus. Arsenic is found by itself in nature, but usually is found in the minerals arsenopyrite, realgar and orpiment. Most of the commercial arsenic in use today is taken from the compound arsenopyrite and extracted by heating.
Arsenic is a known poison. It featured in the movie, "It's a Wonderful Life" when the pharmacist made a powder of arsenic instead of a healing powder for the young Jimmy Stewart character to deliver. Arsenic conducts electricity and is a semiconductor.
As a poison, arsenic exposure can be by inhaling, ingesting, via the skin and through the eyes. It targets and is toxic to the skin, lungs, kidneys, nervous system, the liver, the stomach and gastrointestinal tract and to the reproductive organs. Arsenic is a known carcinogen and causes lung cancer if inhaled. It can also cause skin cancer when in contact with the skin.
It is found in seawater in a small amount and is added to pesticides and wood preservatives. Production of arsenicum is about forty seven thousand tons a year, worldwide.
Other uses for arsenic include the manufacture of shotgun pellets, and in the metal for mirrors and lasers. It is part of light-emitting diodes (LED) as well. It is a bi-product of refining of sulfide ores.