Potassium arsenate is the chemical compound

Chemical compound

A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...

 with the formula

Chemical formula

A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....

  KH₂AsO₄. Other salts are also called potassium arsenate, including K₂HAsO₄ and K₃AsO₄. Each of these species is derived from arsenic acid

Arsenic acid

Arsenic acid is the chemical compound with the formula H3AsO4. More descriptively written as AsO3, 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 only found in solution where it...

:

H₃AsO₄ + KOH → KH₂AsO₄ + H₂O

KH₂AsO₄ + KOH → K₂HAsO₄ + H₂O

K₂HAsO₄ + KOH → K₃AsO₄ + H₂O

These species are closely related to the corresponding potassium phosphate

Potassium phosphate

Potassium phosphate is a generic term for the salts of potassium and phosphate ions including:* Monopotassium phosphate * Dipotassium phosphate * Tripotassium phosphate...

s. The anions H₂AsO₄⁻, HAsO₄²⁻, and AsO₄³⁻ feature tetrahedral AsO₄ with two, one, or no H atoms attached to the oxygen atom(s), respectively.

Although this and related arsenic

Arsenic

Arsenic is a chemical element with the symbol As, atomic number 33 and relative atomic mass 74.92. Arsenic occurs in many minerals, usually in conjunction with sulfur and metals, and also as a pure elemental crystal. It was first documented by Albertus Magnus in 1250.Arsenic is a metalloid...

salts have been prescribed for health purposes, such compounds are highly toxic.