Names | |
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IUPAC name
Sodium dihydrogen phosphate
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Other names
monobasic sodium phosphate;
sodium dihydrogen phosphate; sodium biphosphate |
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Identifiers | |
3D model (Jmol)
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ChEBI | |
ChemSpider | |
ECHA InfoCard | 100.028.591 |
PubChem CID
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UNII | |
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Properties | |
NaH2PO4 | |
Molar mass | 119.98 g/mol |
Appearance | White powder or crystals |
Density | 2.36 g/cm3 (anhydrous) |
59.90 g/100 mL (0°C) | |
Hazards | |
NFPA 704 | |
Flash point | Non-flammable |
Related compounds | |
Other cations
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Monopotassium phosphate Monoammonium phosphate |
Related compounds
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Disodium phosphate Trisodium phosphate |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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what is ?) | (|
Infobox references | |
Monosodium phosphate (MSP), also known as monobasic sodium phosphate and sodium dihydrogen phosphate, is an inorganic compound of sodium with dihydrogen phosphate (H2PO4−) anion. One of many sodium phosphates, it is a common industrial chemical. The salt exists in an anhydrous form, as well as mono- and dihydrates.
The salt is obtained by partial neutralization of phosphoric acid. The pKa of monosodium phosphate is 6.8-7.2 (depending on the physicochemical characteristics during pKa determination).
Heating this salt above 169 °C gives the corresponding sodium acid pyrophosphate:
Phosphates are often used in foods and in water treatment. The pH of such formulations is generally adjusted by mixtures of various sodium phosphates, such as this salt. The sodium chloride equivalent value, or E-Value, is 0.49. It is soluble in 4.5 parts water.
It is added in animal feed, toothpaste, and evaporated milk. It is used as a thickening agent and emulsifier.
Monosodium phosphate is used to detect the presence of magnesium ions in salts. Formation of a white precipitate on the addition of ammonium chloride, ammonium hydroxide and monosodium phosphate to an aqueous or dilute HCl solution of the salt indicates presence of magnesium ions.