arsenate

The arsenate is an ion with the chemical formula . 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. The four oxygen atoms orient around the arsenic atom in a tetrahedral geometry. Resonance disperses the ion's −3 charge across all four oxygen atoms.

Arsenate readily reacts with metals to form arsenate metal compounds. Arsenate is a moderate oxidizer and an electron acceptor, with an electrode potential of +0.56 V for its reduction to arsenite. Due to arsenic having the same valency and similar atomic radius to phosphorus, arsenate shares similar geometry and reactivity with phosphate. Arsenate can replace phosphate in biochemical reactions and is toxic to most organisms. ==Natural occurrence== left|thumb|180x180px|Adamite, a naturally occurring arsenate mineral. Arsenates occur naturally, in hydrated and anhydrous form, in a variety of minerals. Examples of arsenate-containing minerals include adamite, alarsite, annabergite, erythrite and legrandite. When two arsenate ions balance the charge in a formula, it is called diarsenate for example zinc diarsenate, .