Monosodium citrate

Monosodium citrate
Names
	IUPAC name Sodium 2-(carboxymethyl)-2,4-dihydroxy-4-oxobutanoate
	Other names sodium dihydrogen 2-hydroxypropane-1,2,3-tricarboxylate
Identifiers
CAS Number	18996-35-5 ;
3D model (JSmol)	Interactive image ;
ChEBI	CHEBI:53258 ;
ChemSpider	27304 ;
ECHA InfoCard	100.038.834
EC Number	242-734-6;
E number	E331i (antioxidants, ...)
PubChem CID	23662352 ;
RTECS number	GE9750000;
UNII	68538UP9SE ;
CompTox Dashboard (EPA)	DTXSID80872904 ;
	InChI InChI=1S/C6H8O7.Na/c7-3(8)1-6(13,5(11)12)2-4(9)10;/h13H,1-2H2,(H,7,8)(H,9,10)(H,11,12);/q;+1/p-1 Key: HWPKGOGLCKPRLZ-UHFFFAOYSA-M ; InChI=1/C6H8O7.3Na/c7-3(8)1-6(13,5(11)12)2-4(9)10;;;/h13H,1-2H2,(H,7,8)(H,9,10)(H,11,12);;;/q;3*+1/p-3 Key: HRXKRNGNAMMEHJ-DFZHHIFOAL;
	SMILES C(C(=O)O)C(CC(=O)O)(C(=O)[O-])O.[Na+];
Properties
Chemical formula	C6H7NaO7
Molar mass	214.105 g·mol−1
Appearance	white powder ; hygroscopic
Odor	odorless
Melting point	212 °C (414 °F; 485 K)
Boiling point	309.6 °C (589.3 °F; 582.8 K)
Solubility in water	soluble
Solubility	negligible in ethanol
Acidity (pKa)	3.50–3.80
Structure
Crystal structure	Monoclinic
Space group	P21/a (No. 4)
Formula units (Z)	4
Hazards
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	5400 mg/kg (mouse, oral) >2000 mg/kg (rat, dermal)
Safety data sheet (SDS)	Carl Roth
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Last updated September 10, 2025

Monosodium citrate, more correctly, sodium dihydrogen citrate (Latin: natrium citricum acidulatum), is an acid salt of citric acid. Disodium citrate and trisodium citrate are also known. It can be prepared by partial neutralisation of citric acid^[3] with an aqueous solution of sodium bicarbonate or carbonate. It has a slightly acidic taste.^[3]

NaHCO₃ + C₆H₈O₇ → NaC₆H₇O₇ + CO₂ + H₂O

Na₂CO₃ + 2C₆H₈O₇ → 2NaC₆H₇O₇ + CO₂ + H₂O

It is highly soluble in water and practically insoluble in ethanol.^[3] Monosodium citrate is used as an anticoagulant in blood samples.^[4] It is used as an alkalinizing agent to prevent kidney stone disease.^[5] The crystals form as nearly perfect cubes.^[6]

References

↑ "Sodium dihydrogen citrate".
↑ Glusker, Jenny P.; van der Helm, D.; Love, Warner E.; Dornberg, Marilyn L.; Patterson, A. L. (June 1960). "The State of Ionization of Crystalline Sodium Dihydrogen Citrate1" . Journal of the American Chemical Society. 82 (11): 2964–2965. Bibcode:1960JAChS..82.2964G. doi:10.1021/ja01496a071. ISSN 0002-7863 . Retrieved 22 July 2022.
1 2 3 "Monosodium Citrate - Jungbunzlauer". www.jungbunzlauer.com. Retrieved 17 July 2022.
↑ Clinical Hematology: Theory and Procedures, Mary Louise Turgeon
↑ PubChem. "Monosodium citrate". pubchem.ncbi.nlm.nih.gov. Retrieved 2021-08-02.
↑ Hitchcock, David I. (March 1946). "Sodium Hydrogen Citrates" . Journal of the American Chemical Society. 68 (3): 524–525. Bibcode:1946JAChS..68R.524H. doi:10.1021/ja01207a507. ISSN 0002-7863. PMID 21015754 . Retrieved 22 July 2022.

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[1] "Sodium dihydrogen citrate".

[Structure_MSC-2] Glusker, Jenny P.; van der Helm, D.; Love, Warner E.; Dornberg, Marilyn L.; Patterson, A. L. (June 1960). "The State of Ionization of Crystalline Sodium Dihydrogen Citrate1" . Journal of the American Chemical Society. 82 (11): 2964–2965. Bibcode:1960JAChS..82.2964G. doi:10.1021/ja01496a071. ISSN 0002-7863 . Retrieved 22 July 2022.

[ref3-3] 1 2 3 "Monosodium Citrate - Jungbunzlauer". www.jungbunzlauer.com. Retrieved 17 July 2022.

[4] Clinical Hematology: Theory and Procedures, Mary Louise Turgeon

[5] PubChem. "Monosodium citrate". pubchem.ncbi.nlm.nih.gov. Retrieved 2021-08-02.

[Structure_NaH2Cit_2-6] Hitchcock, David I. (March 1946). "Sodium Hydrogen Citrates" . Journal of the American Chemical Society. 68 (3): 524–525. Bibcode:1946JAChS..68R.524H. doi:10.1021/ja01207a507. ISSN 0002-7863. PMID 21015754 . Retrieved 22 July 2022.

[1]

[2]

[3]

[4]

[5]

[6]

Names


IUPAC name Sodium 2-(carboxymethyl)-2,4-dihydroxy-4-oxobutanoate^[1]
Other names sodium dihydrogen 2-hydroxypropane-1,2,3-tricarboxylate
Identifiers
CAS Number	18996-35-5 ^Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:53258 ^Y
ChemSpider	27304 ^N
ECHA InfoCard	100.038.834
EC Number	242-734-6
E number	E331i (antioxidants, ...)
PubChem CID	23662352
RTECS number	GE9750000
UNII	68538UP9SE ^Y
CompTox Dashboard (EPA)	DTXSID80872904
InChI InChI=1S/C6H8O7.Na/c7-3(8)1-6(13,5(11)12)2-4(9)10;/h13H,1-2H2,(H,7,8)(H,9,10)(H,11,12);/q;+1/p-1^N Key: HWPKGOGLCKPRLZ-UHFFFAOYSA-M^N InChI=1/C6H8O7.3Na/c7-3(8)1-6(13,5(11)12)2-4(9)10;;;/h13H,1-2H2,(H,7,8)(H,9,10)(H,11,12);;;/q;3*+1/p-3 Key: HRXKRNGNAMMEHJ-DFZHHIFOAL
SMILES C(C(=O)O)C(CC(=O)O)(C(=O)[O-])O.[Na+]
Properties
Chemical formula	C₆H₇NaO₇
Molar mass	214.105 g·mol⁻¹
Appearance	white powder hygroscopic
Odor	odorless
Melting point	212 °C (414 °F; 485 K)
Boiling point	309.6 °C (589.3 °F; 582.8 K)
Solubility in water	soluble
Solubility	negligible in ethanol
Acidity (pK_a)	3.50–3.80
Structure^[2]
Crystal structure	Monoclinic
Space group	P21/a (No. 4)
Formula units (Z)	4
Hazards
Lethal dose or concentration (LD, LC):
LD₅₀ (median dose)	5400 mg/kg (mouse, oral) >2000 mg/kg (rat, dermal)
Safety data sheet (SDS)	Carl Roth
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is ^YN ?) Infobox references