The three most common arsenic allotropes are grey, yellow, and black arsenic, with grey being the most common. Grey arsenic (α-As, space group R3m No. 166) adopts a double-layered structure consisting of many interlocked… See more

Compounds of arsenic resemble, in some respects, those of phosphorus, which occupies the same group (column) of the periodic table. The most common oxidation states for arsenic are: −3 in the arsenides, which are a… See more

Arsenic is the 53rd most abundant element in the Earth's crust, comprising about 1.5 parts per million (0.00015%). Typical background concentrations of arsenic do not exceed 3 ng/m in the atmosphere; 100 mg/kg in so… See more

The word arsenic has its origin in the Syriac word ܙܪܢܝܟܐ zarnika, from Arabic al-zarnīḵ الزرنيخ 'the orpiment', based on Persian zar ("gold") from the word زرنيخ zarnikh, meaning "yellow" (literally "gold-colored") and hence … See more

The toxicity of arsenic to insects, bacteria, and fungi led to its use as a wood preservative. In the 1930s, a process of treating wood with chromated copper arsenate (also known as CCA or Tanalith) was invent… See more