Sodium citrate

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Sodium citrate
Sodium citrate
General
Systematic name trisodium 2-hydroxypropane-1,2,3-tricarboxylate
Other names citrosodine; trisodium citrate; citric acid, trisodium salt
Molecular formula Na3C6H5O7
SMILES [Na+].[Na+].[Na+]. O=C([O-])CC(O)(CC(=O)[O-])C([O-])=O
Molar mass 258.07 g/mol
Appearance White crystalline powder
CAS number [68-04-2] (anhydrous); [6132-04-3] (dihydrate)
Properties
Density and phase ~ 1.7 g/cm³ solid
Solubility in water 72 g/100 ml
Melting point 150 °C
Boiling point Decomposes
Acidity (pKa)  ?
Basicity (pKb)  ?
Structure
Crystal structure  ?
Dipole moment  ? D
Hazards
MSDS External MSDS
Main hazards Irritant
NFPA 704

0
1
0
 
Flash point  ?°C
R/S statement R: ?
S: ?
RTECS number  ?
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Related compounds
Related compounds calcium citrate, citric acid
Except where noted otherwise, data are given for
materials in their standard state (at 25 °C, 100 kPa)
Infobox disclaimer and references

Sodium citrate is the sodium salt of citric acid with the chemical formula of Na3C6H5O7.

In this sense, it is similar to calcium citrate. Like citric acid, sodium citrate has a sour taste. Like other salts, however, it also has a salty taste. For this reason, citrates such as sodium and calcium citrate are commonly known as sour salt (sometimes, people refer to citric acid as sour salt). It is chiefly used as a food additive, usually for flavor or as a preservative. Sodium citrate gives club soda both its sour and salty flavors. Sodium citrate is common in lemon-lime soft drinks, and it is partly what causes them to have their sour taste.

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, disrupting the blood clotting mechanism.

As a conjugate base of a weak acid, citrate can perform as a buffering agent, resisting changes in pH. Sodium citrate is used to control acidity in some substances, such as gelatin desserts. It can be found the mini milk containers used with coffee machines. It is also the last ingredient in Welch's Concord Grape Jam.

Research from the British Journal of Sports Medicine (2003) showed that use of sodium citrate (approx. 37 grams) improved running performance over 5 km by 30 seconds. [1]

Sodium citrate is used to relieve discomfort in urinary tract infections such as cystitis, and is also used as an osmotic laxative.

[edit] References

  1. ^ Oopik, V et al 2003; 37: 485-489

[edit] External links


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