Element Arsenic, As, Metalloid

33
As
74.9216
Arsenic

 [Ar]
4s2
3d10
4p3

Arsenic History

Arsenic has been known from high antiquity. In 3rd - 2rd millenua BC some alloys with 4-5% Arsenic were available. Arsenic's poisoning properties had become known in Middle Ages, and even before that Pedanius Dioscorides recommended to persons suffered from asthma to inhale the vapours of heated resin and realgar. Paracelsus extensively applied white arsenic and other arsenic compounds for treatment. The Latin arsenicum and Greek arsenikon originated from the Greek word which stands for "masculine".

Arsenic Occurrence

The crustal abundance is small: 5x10-4%, that means 5 gper ton (1000 kg), the same as for Germanium, tin, tungsten or bromine. In minerals arsenic is accompanied by iron, copper, cobalt and nickel.

Arsenopyrite also called mispickel (FeAsS) is the most common arsenic-bearing mineral. It may be considered as common pyrite with a sulphur atom replaced by one atom of arsenic. Such compounds are called sulphosalts. Sulphosalts may also contain noble metals of platinum group.

Arsenic abundance in soil is from 0.1 to 40 mg per kilogram. However in the areas of arsenic ores deposits, as in Switzerland and New Zealand, arsenic concentration in soil may be much higher, reaching 8 g/kg. Such areas are deadly for plants and sickening for animals. It is typical for heaths and deserts, where arsenic is not flushed out from the soil. Clay rocks are also richer with arsenic, with fourfold concentration. Some countries establish the maximum permissible concentration of arsenic in soil.

Arsenic concentration in living matter is 6x10-16%, that is 6 µg/kg. Some kinds of seaweed are able to concentrate so much arsenic that become dangerous for people. Moreover, such algae are able to grow and breed in pure solutions of arsenous acid. Such seaweeds are used in some Asian countries as a rat poison. Even seaweeds of pure waters of Norwegian fjords may contain 0.1 g/kg of arsenic. In human organism arsenic is concentrated in brain, muscles, hair and nails.

Arsenic Neighbours


Periodic Table of Chemical Elements