Sodium citrate

Sodium citrate may refer to any of the sodium salts of citric acid (though most commonly the third): The three forms of salt are collectively known by the E number E331.
 * Monosodium citrate
 * Disodium citrate
 * Trisodium citrate

Food
Sodium citrates are used as acidity regulators in food and drinks, and also as emulsifiers for oils. They enable cheeses to melt without becoming greasy. It reduces the acidity of food as well. It is generally considered safe and is considered GRAS by the FDA.

Blood clotting inhibitor
Sodium citrate is used to prevent donated blood from clotting in storage. It is also used in a laboratory, before an operation, to determine whether a person's blood is too thick and might cause a blood clot, or if the blood is too thin to safely operate. Sodium citrate is used in medical contexts as an alkalinizing agent in place of sodium bicarbonate, to neutralize excess acid in the blood and urine.

Metabolic acidosis
It has applications for the treatment of metabolic acidosis and chronic kidney disease.

Ferrous nanoparticles
Along with oleic acid, sodium citrate may be used in the synthesis of magnetic Fe3O4 nanoparticle coatings.