Sodium arsenate is the

inorganic compound An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds⁠that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistry''. Inorgan ...

with the

formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwe ...

Na₃AsO₄. Related salts are also called sodium arsenate, including Na₂HAsO₄ (

disodium hydrogen arsenate Disodium hydrogen arsenate is the inorganic compound with the formula Na2HAsO4.7H2O. The compound consists of a salt and seven molecules of water of crystallization although for simplicity the formula usually omits the water component. The other ...

) and NaH₂AsO₄ (

sodium dihydrogen arsenate Sodium dihydrogen arsenate is the inorganic compound with the formula NaH2AsO4. Related salts are also called sodium arsenate, including Na2HAsO4 ( disodium hydrogen arsenate) and NaH2AsO4 (sodium dihydrogen arsenate). Sodium dihydrogen arsenat ...

). The trisodium salt is a white or colourless solid that is highly toxic. It is usually handled as the dodecahydrate Na₃AsO₄^.12H₂O. The compound can be obtained by neutralizing

arsenic acid Arsenic acid or arsoric acid is the chemical compound with the chemical formula, formula . More descriptively written as , this colorless acid is the arsenic analogue of phosphoric acid. Arsenate and phosphate salts behave very similarly. Arsenic ...

: :H₃AsO₄ + 3 NaOH → Na₃AsO₄ + 3 H₂O The salt (as its dodecahydrate) is isomorphous with

trisodium phosphate Trisodium phosphate (TSP) is an inorganic compound with the chemical formula . It is a white, granular or crystalline solid, highly soluble in water, producing an alkaline solution. TSP is used as a cleaning agent, builder, lubricant, food addi ...

.Remy, Francis; Guerin, Henri "Radiocrystallographic study of dodecahydrate trisodium arsenate and vanadate Na3AsO4.12H2O and Na3VO4.12H2O, and some hydrates of fluorinated or hydroxylated salts of general formula: M3XO4.xMY.(10 - x)H2O where M = Na, K; X = P, As, V and Y = F, OH" Bulletin de la Société Chimique de France 1970, vol. 6, pp. 2073-8. The anion AsO₄^3- exists at high pH, but below pH 11.5, it converts to HAsO₄^2- (also written HOAsO₃^2-).

References

Arsenates Sodium compounds {{inorganic-compound-stub