Calcium hydrogenphosphate dihydrate
[CAS# 7789-77-7]

Identification

• Classification: Inorganic chemical industry >> Inorganic salt >> Phosphides, metal phosphoric acid, metaphosphoric acid, hypophosphorous acid and pyrophosphate
• Name: Calcium hydrogenphosphate dihydrate
• Molecular Formula: CaHPO₄.2(H₂O)
• Molecular Weight: 172.09
• CAS Registry Number: 7789-77-7
• EC Number: 616-542-1
• SMILES: O.O.OP(=O)([O-])[O-].[Ca+2]

Properties

• Solubility: Slightly soluble (water)
• Density: 2.306 g/mL
• Melting point: 109 °C

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335
• Safety Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin irritation	Skin Irrit.	2	H315

Discovery and Applications

Dicalcium phosphate dihydrate, with the chemical formula CaHPO4·2H2O, consists of calcium ions (Ca²?), hydrogen phosphate ions (HPO4²?), and water molecules (H2O). Its dihydrate form indicates the presence of two water molecules per unit of the compound, affecting its solubility and crystal structure.

In pharmaceuticals, Dicalcium phosphate dihydrate is the active ingredient in antacids and oral calcium supplements. It helps neutralize stomach acid, relieving indigestion, heartburn, and related gastrointestinal discomfort. As a calcium supplement, it supports bone health and prevents calcium deficiency. The compound is also used as a tablet binder and filler in pharmaceutical formulations. It ensures the cohesion of tablet ingredients, facilitates their compression into solid dosage forms, and enhances the stability and solubility of drugs.

Dicalcium phosphate dihydrate is used as a food additive (E341) in various processed foods and beverages. It acts as a buffer and anti-caking agent, maintaining pH balance and preventing caking of powdered products. Its inclusion in fortified foods increases calcium content, contributing to dietary intake and nutritional balance.

In agriculture, the compound is added to animal feed as a calcium and phosphorus supplement for livestock and poultry. It supports bone development, eggshell formation and overall growth in poultry, ensuring optimal health and productivity. Dicalcium phosphate dihydrate can be used in water treatment processes, where it acts as a coagulant and flocculant. It helps remove suspended particles and impurities from water, improving the clarity and quality of drinking and industrial water.

References

2023. Febuxostat solubilization and stabilization approach using solid dispersion method: Synergistic effect of dicalcium phosphate dehydrate and chitosan. International Journal of Biological Macromolecules, 253(8).
DOI: 10.1016/j.ijbiomac.2023.127266

2024. Repair of a rat calvaria defect with injectable strontium (Sr)‐doped polyphosphate dicalcium phosphate dehydrate (P‐DCPD) ceramic bone grafts. Journal of biomedical materials research. Part B, Applied biomaterials, 112(2).
DOI: 10.1002/jbm.b.35388

2024. Simultaneous Regulation of the Mechanical/Osteogenic Capacity of Brushite Calcium Phosphate Cement by Incorporating with Poly(ethylene glycol) Dicarboxylic Acid. ACS Biomaterials Science & Engineering, 10(3).
DOI: 10.1021/acsbiomaterials.3c00886