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Diammonium phosphate
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<p>Diammonium phosphate (DAP; <a href="/facts/IUPAC/2AV6myCK">IUPAC</a> name diammonium hydrogen phosphate; chemical formula (NH4)2(HPO4)) is one of a series of <a href="/facts/Water/0lkXnJPK">water</a>-<a href="/facts/Soluble/kLE9h3Jb">soluble</a> <a href="/facts/Ammonium_phosphate/SAr9wdvW">ammonium phosphate</a> <a href="/facts/Salt_(chemistry)/lsSKwGpn">salts</a> that can be produced when <a href="/facts/Ammonia/MtLtJFtz">ammonia</a> reacts with <a href="/facts/Phosphoric_acid/l6NbwyCv">phosphoric acid</a>. </p><p>Solid diammonium phosphate shows a dissociation pressure of ammonia as given by the following expression and equation: </p> (NH4)2HPO4(s) ⇌ NH3(g) + (NH4)H2PO4(s) <p>At 100 °C, the dissociation pressure of diammonium phosphate is approximately 5 mmHg. </p><p>According to the diammonium phosphate <a href="/facts/Safety_data_sheet/jbshEV2W">MSDS</a> from CF Industries, Inc., decomposition starts as low as 70 °C: "Hazardous Decomposition Products: Gradually loses ammonia when exposed to air at room temperature. Decomposes to ammonia and <a href="/facts/Monoammonium_phosphate/HYa8DmMo">monoammonium phosphate</a> at around 70 °C (158 °F). At 155 °C (311 °F), DAP emits phosphorus oxides, <a href="/facts/Nitrogen_oxide/ved7hE6X">nitrogen oxides</a> and ammonia." </p>