Trisodium citrate

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Sodium citrate
Sodium citrate
IUPAC names
Trisodium citrate
Trisodium 2-hydroxypropane-1,2,3-tricarboxylate
Other names
Citric acid, trisodium salt
Sodium citrate
68-04-2 YesY
6132-04-3 (dihydrate) YesY
6858-44-2 (pentahydrate) YesY
ChemSpider 5989 N
Jmol interactive 3D Image
PubChem 6224
RTECS number GE8300000
Molar mass 258.06 g/mol (anhydrous), 294.10 g/mol (dihydrate)
Appearance White crystalline powder
Density 1.7 g/cm3
Melting point >300 °C
hydrates lose water ca. 150 C
Boiling point Decomposes
Pentahydrate form: 92 g/100 g H2O (25 °C)[1]
Main hazards Irritant
Safety data sheet External MSDS
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
Lethal dose or concentration (LD, LC):
1548 mg/kg (intraperitoneal, rat)[2]
Related compounds
Related compounds
Monosodium citrate
Disodium citrate
Calcium citrate
Citric acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YesYN ?)
Infobox references

Trisodium citrate has the chemical formula of Na3C6H5O7. It is sometimes referred to simply as sodium citrate, though sodium citrate can refer to any of the three sodium salts of citric acid. It possesses a saline, mildly tart flavor. It is mildly basic and can be used along with citric acid to make biologically compatible buffers.



Sodium citrate is chiefly used as a food additive, usually for flavor or as a preservative. Its E number is E331. Sodium citrate is employed as a flavoring agent in certain varieties of club soda. Sodium citrate is common as an ingredient in Bratwurst, and is also used in commercial ready to drink beverages and drink mixes, contributing a tart flavor. It is found in ice-cream, jams, sweets, milk powder, processed cheeses, carbonated beverages, and wine.


As a conjugate base of a weak acid, citrate can perform as a buffering agent or acidity regulator, resisting changes in pH. Sodium citrate is used to control acidity in some substances, such as gelatin desserts. It can be found in the mini milk containers used with coffee machines. The compound is the product of antacids, such as Alka-Seltzer, when they are dissolved in water. A solution of 5 g/100 ml water at 25ºC is 7.5 – 9.0.

Medical uses[edit]

In 1914, the Belgian doctor Albert Hustin and the Argentine physician and researcher Luis Agote successfully used sodium citrate as an anticoagulant in blood transfusions. It continues to be used today in blood collection tubes and for the preservation of blood in blood banks. The citrate ion chelates calcium ions in the blood by forming calcium citrate complexes, disrupting the blood clotting mechanism.

In 2003, Oöpik, et al., showed the use of sodium citrate (0.5 grams per kg of body weight) improved running performance over 5 km by 30 seconds.[3]

Sodium citrate is used to relieve discomfort in urinary tract infections, such as cystitis, to reduce the acidosis seen in distal renal tubular acidosis, and can also be used as an osmotic laxative. It is a major component of the WHO Oral Rehydration Solution.

It is used as an antacid, especially prior to anaesthesia, for caesarian section procedures to reduce the risks associated with the aspiration of gastric contents.

Boiler descaling[edit]

Sodium citrate is a particularly effective agent for removal of carbonate scale from boilers without removing them from operation[4] and for cleaning automobile radiators.[5]

See also[edit]