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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] The four oxygen atoms orient around the arsenic atom in a tetrahedral geometry. [2]
The highly basic arsenate ion (AsO 3− 4 ) is the product of the third ionization. Unlike phosphoric acid, arsenic acid is an oxidizer, as illustrated by its ability to convert iodide to iodine .
The researchers conjectured that historically these photosynthesizing organisms produced the arsenates that allowed the arsenate-reducing bacteria to thrive. [14] In humans, arsenite inhibits pyruvate dehydrogenase (PDH complex) in the pyruvate-acetyl CoA reaction, by binding to the –SH group of lipoamide, a participant coenzyme.
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]
Arsenate minerals usually refer to the naturally occurring orthoarsenates, possessing the (AsO 4) 3− anion group and, more rarely, other arsenates with anions like AsO 3 (OH) 2− (also written HAsO 4 2−) (example: pharmacolite Ca(AsO 3 OH). 2H 2 O) or (very rarely) [AsO 2 (OH) 2] − (example: andyrobertsite). Arsenite minerals are much ...
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.
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]
An arsenate arsenite is a chemical compound or salt that contains arsenate and arsenite anions (AsO 3 3-and AsO 4 3-). These are mixed anion compounds or mixed valence compounds. Some have third anions. Most known substances are minerals, but a few artificial arsenate arsenite compounds have been made. Many of the minerals are in the Hematolite ...