arsenite

In chemistry, an arsenite is a chemical compound containing an arsenic oxyanion where arsenic has oxidation state +3. Note that in fields that commonly deal with groundwater chemistry, arsenite is used generically to identify soluble AsIII anions. IUPAC have recommended that arsenite compounds are to be named as arsenate(III), for example ortho-arsenite is called trioxidoarsenate(III). Ortho-arsenite contrasts to the corresponding anions of the lighter members of group 15, phosphite which has the structure and nitrite, which is bent.

A number of different arsenite anions are known: ortho-arsenite, an ion of arsenous acid, with a pyramidal shape {{chem2|(AsO2−)_{n}|}} meta-arsenite, a polymeric chain anion. pyro-arsenite, catena-triarsenite, catena-tetraarsenite, cyclo-tetraarsenite {{chem2|(As6O11(4−))_{n}|}}, a polymeric anion