Sodium Phosphate – Na3PO4

What is Sodium Phosphate?

Sodium phosphate is also known as phospho soda with the formula Na₃PO₄ is a saline cathartic that is familiar to radiologists since it is often used as a cleansing agent prior to double contrast barium enema.

Sodium phosphate cradles are the most widely recognized, yet there is broad utilization of potassium phosphate buffer and blends of sodium and potassium. Many compounds of pharmaceutical interest are formulated in sodium phosphate buffers.

Other names – Trisodium phosphate, Sodium orthophosphate, Tribasic sodium phosphate

Na3PO4	Sodium Phosphate
Density	1.62 g/cm³
Molecular Weight/ Molar Mass	163.94 g/mol
Boiling Point	100 °C
Melting Point	1,583 °C
Chemical Formula	Na3PO4

Physical Properties of Sodium Phosphate – Na₃PO₄

Odour	Odourless
Appearance	Off-white powder
Covalently-Bonded Unit	4
Complexity	36.8
Hydrogen Bond Acceptor	4
Solubility	Soluble in water

Chemical Properties of Sodium Phosphate – Na₃PO₄

• Sodium phosphate reacts with hydrochloric acid forms phosphoric acid and sodium chloride. The chemical reaction is given below.

Na₃PO₄ + 3HCl → H₃PO₄ + 3NaCl

• Sodium phosphate reacts with calcium chloride results in the formation of calcium phosphate and sodium chloride. The chemical reaction is given below.

2Na₃PO₄ + 3CaCl₂ → 6NaCl + Ca₃(PO₄)₂

Uses of Sodium Phosphate – Na₃PO₄

• Short-term, local treatment of inflammation with neomycin as bacterial prophylaxis.
• Used after glaucoma surgery or after cataract surgery.
• Used as a mild laxative, stimulates emptying of gall-bladder.
• One of the most palatable of the saline laxatives. It is also used in the form of the oral solution (see below) as an antihypercal- cemic.
• Used to control the pH of water hardness precipitation and control agent in mildly acidic solutions.