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Sodium arsenate
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<p>Sodium arsenate is the <a href="/facts/Inorganic_compound/TfFfzxSz">inorganic compound</a> with the <a href="/facts/Chemical_formula/hghUtthl">formula</a> Na3AsO4. Related salts are also called sodium arsenate, including Na2HAsO4 (<a href="/facts/Disodium_hydrogen_arsenate/oRCNIfUb">disodium hydrogen arsenate</a>) and NaH2AsO4 (<a href="/facts/Sodium_dihydrogen_arsenate/hNJCpeEw">sodium dihydrogen arsenate</a>). The trisodium salt is a white or colourless solid that is highly toxic. It is usually handled as the dodecahydrate Na3AsO4.12H2O. </p><p>The compound can be obtained by neutralizing <a href="/facts/Arsenic_acid/NURfJaGw">arsenic acid</a>: </p> H3AsO4 + 3 NaOH → Na3AsO4 + 3 H2O <p>The salt (as its dodecahydrate) is isomorphous with <a href="/facts/Trisodium_phosphate/ho0E4DcI">trisodium phosphate</a>. The anion AsO43- exists at high pH, but below pH 11.5, it converts to HAsO42- (also written HOAsO32-). </p>