Trimagnesium Phosphate – an inorganic compound

Trimagnesium Phosphate – an inorganic compound

Trimagnesium phosphate also known as magnesium phosphate tribasic, is a chemical compound with the formula Mg3(PO4)2.xH2O. They are magnesium acid salts of phosphoric acid, with varying amounts of water of crystallization: x = 0, 5, 8, 22. It is a white, crystalline solid that is commonly used as a food additive, a dietary supplement, and as a treatment for heartburn and indigestion. In the food industry, it is used as a firming agent and to regulate the acidity of certain foods. In the medical field, it is used as an antacid to neutralize excess stomach acid and relieve symptoms of indigestion, heartburn, and upset stomach.


It is a white, crystalline powder that is commonly used as a dietary supplement due to its high magnesium content. Magnesium is an essential mineral that plays a key role in various bodily processes, including nerve and muscle function, protein synthesis, and energy production.

  • Chemical formula: Mg3O8P2
  • Molar mass: 262.855 g·mol−1
  • Appearance: White crystalline powder
  • Melting point: 1,184 °C (2,163 °F; 1,457 K)
  • Solubility in water: Insoluble
  • Solubility product (Ksp): 1.04×10−24
  • Solubility: Soluble in salt solution
Trimagnesium Phosphate


The octahydrate is found in nature as the mineral bobierrite. The anhydrous compound is obtained by heating the hydrates to 400 °C. It is isostructural with cobalt(II) phosphate. The metal ions occupy both octahedral (six-coordinate) and pentacoordinate sites in a 1:2 ratio.


The compound is also used in the manufacture of fertilizers, ceramics, and dental cements. Magnesium is an important mineral that plays a vital role in various physiological processes, such as energy production, muscle function, and the maintenance of strong bones.

In addition to its use as a supplement, trimagnesium phosphate can also be used in the food industry as a firming agent and as a leavening agent in baking. It is also used in certain medical applications, such as as an antacid to neutralize excess stomach acid.


Magnesium phosphate tribasic is listed on the FDA’s generally recognized as safe, or GRAS, list of substances. It’s important to note that while magnesium is an important nutrient, taking too much of it can cause adverse side effects, such as diarrhea and stomach cramps. It is important to consult with a healthcare provider before taking any new dietary supplements, including trimagnesium phosphate.