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The arsenate is an ion with the chemical formula AsO 3− 4. [1] Bonding in arsenate consists of a central arsenic atom, with oxidation state +5, double bonded to one oxygen atom and single bonded to a further three oxygen atoms. [ 2 ]
Arsenic trioxide powder.. 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 alloy-like intermetallic compounds, +3 in the arsenites, and +5 in the arsenates and most organoarsenic compounds.
Arsenate (+5 oxidation state) is the dominant form of arsenic in surface water, while arsenite (+3 oxidation state) is the dominant form in hypoxic to anoxic environments. Arsenite is more soluble and mobile than arsenate. Many species of bacteria can transform arsenite to arsenate in anoxic conditions by using arsenite as an electron donor. [189]
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 HPO 2− 3 and nitrite, NO − 2 which is bent. [1]
Calcium arsenate is commonly prepared from disodium hydrogen arsenate and calcium chloride: 2 Na 2 H[AsO 4] + 3 CaCl 2 → 4 NaCl + Ca 3 [AsO 4] 2 + 2 HCl. In the 1920s, it was made in large vats by mixing calcium oxide and arsenic oxide. [6] In the United States, 1360 metric tons were produced in 1919, 4540 in 1920, and 7270 in 1922. [1]
Sodium arsenate is the inorganic compound with the formula Na 3 AsO 4. Related salts are also called sodium arsenate, including Na 2 HAsO 4 (disodium hydrogen arsenate) and NaH 2 AsO 4 (sodium dihydrogen arsenate). The trisodium salt is a white or colourless solid that is highly toxic. It is usually handled as the dodecahydrate Na 3 AsO 4. 12H ...
The group 1 alkali metals and the group 2, alkaline earth metals, form arsenides with isolated arsenic atoms.They form upon heating arsenic powder with excess sodium gives sodium arsenide (Na 3 As).
Arsenic acid or arsoric acid is the chemical compound with the formula H 3 AsO 4. More descriptively written as AsO(OH) 3, this colorless acid is the arsenic analogue of phosphoric acid. Arsenate and phosphate salts behave very similarly. Arsenic acid as such has not been isolated, but is only found in solution, where it is largely ionized.