Trisodium Citrate Dihydrate (CAS 6132-04-3) is the sodium salt of citric acid, a naturally occurring organic acid. Its chemical structure, Na3C6H5O7·2H2O, reveals a compound that offers a unique combination of properties making it a valuable asset across numerous industries. Understanding its chemistry is key to appreciating its broad applicability, from food science to medical treatments. Sourcing this chemical from reliable manufacturers, often located in China, ensures access to its potent chemical functionalities.

Citric acid itself is a tricarboxylic acid, meaning it possesses three carboxyl groups that can readily donate protons. When reacted with sodium hydroxide or sodium carbonate, these carboxyl groups are neutralized to form sodium salts. Trisodium citrate represents the complete neutralization of citric acid, yielding a salt that is mildly alkaline in aqueous solutions. This property is fundamental to its role as a buffering agent, capable of stabilizing pH within a specific range, typically between 7.5 and 9.0. This buffering capacity is crucial for processes where maintaining a stable pH is critical, such as in biochemical assays or certain food formulations.

The 'dihydrate' designation in Trisodium Citrate Dihydrate indicates that each molecule of the salt is associated with two molecules of water of hydration. This crystalline form influences its physical properties, such as solubility and handling. It is highly soluble in water, readily dissolving to form a clear solution, but is insoluble in ethanol. Its melting point is significantly high, typically decomposing rather than melting cleanly at temperatures above 300°C. These physical characteristics are important considerations for chemical purchasers when designing formulations or storage protocols.

Furthermore, the citrate ion itself possesses chelating abilities, meaning it can bind to metal ions. This property is leveraged in various applications, including acting as an antioxidant by sequestering pro-oxidant metal ions, and in medical contexts as an anticoagulant by binding calcium ions. The chemical versatility stemming from its salt form, buffering capability, and chelating nature makes Trisodium Citrate Dihydrate a highly sought-after chemical. For ingredient purchasers, understanding these underlying chemical principles ensures informed decision-making when selecting suppliers and specifying product grades, with China being a significant source for this important chemical compound.