1 Answers
In chemistry, an arsenite is a chemical compound containing an arsenic oxoanion where arsenic has oxidation state +3. Note that in fields that commonly deal with groundwater chemistry, arsenite is used generically to identify soluble As anions. IUPAC have recommended that arsenite compounds are to be named as arsenate, for example ortho-arsenite is called trioxidoarsenate. Ortho-arsenite contrasts to the corresponding anions of the lighter members of group 15, phosphite which has the structure HPO3 and nitrite, NO2 which is bent.
A number of different arsenite anions are known:
In all of these the geometry around the As centers are approximately trigonal, the lone pair on the arsenic atom is stereochemically active. Well known examples of arsenites include sodium meta-arsenite which contains a polymeric linear anion, n, and silver ortho-arsenite, Ag3AsO3, which contains the trigonal AsO3 anion.