Sodium formate

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Sodium formate
Structural formula of sodium formate
Ball-and-stick model of the formate anion
The sodium cation
Other names
formic acid, sodium salt, sodium hydrocarbon dioxide
141-53-7 YesY
ChemSpider 8517 YesY
EC Number 205-488-0
Jmol interactive 3D Image
PubChem 2723810
UNII 387AD98770 YesY
Molar mass 68.007 g/mol
Appearance white granules
Density 1.92 g/cm3 (20 °C)
Melting point 253 °C (487 °F; 526 K)
Boiling point decomposes
43.82 g/100 mL (0 °C)
97.2 g/100 mL (20 °C)
160 g/100 mL (100 °C)
Solubility insoluble in ether
soluble in glycerol, alcohol, formic acid
Acidity (pKa) 7.0-8.5 (0.1M)
82.7 J/mol K
103.8 J/mol K
-666.5 kJ/mol
-599.9 kJ/mol
not listed
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Sodium formate, HCOONa, is the sodium salt of formic acid, HCOOH. It usually appears as a white deliquescent powder.


Sodium formate is used in several fabric dyeing and printing processes. It is also used as a buffering agent for strong mineral acids to increase their pH, as a food additive (E237), and as a de-icing agent.

In structural biology, sodium formate can be used as a cryoprotectant for X-ray diffraction experiments on protein crystals,[1] which are typically conducted at a temperature of 100K to reduce the effects of radiation damage.


Sodium formate can be prepared in the laboratory by neutralizing formic acid with sodium carbonate. It can also be obtained by reacting chloroform with an alcoholic solution of sodium hydroxide.

CHCl3 + 4NaOH → HCOONa + 3NaCl + 2H2O

or by reacting sodium hydroxide with chloral hydrate.

C2HCl3(OH)2 + NaOHCHCl3 + HCOONa + H2O

The latter method is, in general, preferred to the former because the low aqueous solubility of CHCl3 makes it easier to separate out from the sodium formate solution, by fractional crystallization, than the soluble NaCl would be.

For commercial use, sodium formate is produced by absorbing carbon monoxide under pressure in solid sodium hydroxide at 160 °C.


Sodium formate may also be created via the haloform reaction between ethanol and sodium hypochlorite in the presence of a base. This procedure is well documented for the preparation of chloroform.

See also[edit]


  1. ^ Bujacz, G.; Wrzesniewska, B.; Bujacz, A. (2010), "Cryoprotection properties of salts of organic acids: a case study for a tetragonal crystal of HEW lysozyme", Acta Crystallographica Section D: Biological Crystallography 66 (7), pp. 789–796, doi:10.1107/S0907444910015416