Sodium arsenate is the
inorganic compound
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemi ...
with the
formula Na
3AsO
4. Related salts are also called sodium arsenate, including Na
2HAsO
4 (
disodium hydrogen arsenate) and NaH
2AsO
4 (
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 arsenate ...
). The trisodium salt is a white or colourless solid that is highly toxic. It is usually handled as the dodecahydrate Na
3AsO
4.12H
2O.
The compound can be obtained by neutralizing
arsenic acid
Arsenic acid or trihydrogen arsenate is the chemical compound with the formula . More descriptively written as , this colorless acid is the arsenic analogue of phosphoric acid. Arsenate and phosphate salts behave very similarly. Arsenic acid as ...
:
:H
3AsO
4 + 3 NaOH → Na
3AsO
4 + 3 H
2O
The salt (as its dodecahydrate) is isomorphous with
trisodium phosphate.
[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 AsO
43- exists at high pH, but below pH 11.5, it converts to HAsO
42- (also written HOAsO
32-).
References
Arsenates
Sodium compounds
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