Molar Mass of Calcium Phosphate (Ca₃(PO₄)₂)

Each row shows how much mass one element contributes to the total for Ca₃(PO₄)₂.

Save a printable summary, revision sheet, practice worksheet, or laboratory reference for Calcium Phosphate (Ca₃(PO₄)₂).

Without looking above, write the atom count for Ca₃(PO₄)₂, then compute the molar mass. Check your answer against 310.174 g/mol.

Next challenge: how many grams are in 0.250 mol of Calcium Phosphate? Multiply 0.250 × 310.174 to get 77.544 g.

Rock phosphate mining and processing generate phosphogypsum byproducts and can contribute to phosphate runoff and eutrophication if not managed carefully.

The principal mineral component (as hydroxyapatite) of bone and tooth enamel in vertebrates; essential dietary source of calcium and phosphorus for skeletal mineralization.

Preparation and production

Precipitated in the laboratory by combining soluble calcium salts (CaCl₂) with soluble phosphate salts (Na₃PO₄ or (NH₄)₂HPO₄) under controlled pH. Industrially derived from mined phosphate rock, or produced as a purified food/pharmaceutical-grade precipitate from milk processing byproducts and controlled precipitation reactions.

Global phosphate rock mining (predominantly calcium phosphate minerals) exceeds 220 million tonnes annually, the overwhelming majority destined for fertilizer production; food- and pharmaceutical-grade tricalcium phosphate represents a much smaller specialty market.

Bone ash, an impure form of calcium phosphate, was used in ceramics and as a fertilizer amendment long before its chemical composition was understood. Justus von Liebig's mid-19th-century studies of mineral nutrition helped establish phosphate's essential role in plant growth, spurring the development of superphosphate fertilizer from phosphate rock treated with sulfuric acid — a technology patented by John Bennet Lawes in 1842 that launched the modern chemical fertilizer industry.

Known through bone ash use since antiquity; chemical characterization as calcium phosphate advanced through 18th–19th century mineral and agricultural chemistry, notably by Liebig and Lawes.

Interesting facts

• About 99% of the calcium in the human body is stored as calcium phosphate mineral in bones and teeth.
• Phosphate rock reserves are geographically concentrated, with Morocco holding the majority of the world's known deposits — a geopolitical factor in global food security.
• The calcium phosphate transfection method, developed in the 1970s, remains a widely used and inexpensive way to introduce DNA into cells in research labs today.
• Bone china gets its name and translucent quality from the calcium phosphate derived from bone ash mixed into the ceramic formula.

Comparison with similar compounds

Ca₃(PO₄)₂ (310.18 g/mol) represents idealized tricalcium phosphate stoichiometry, while the actual bone and tooth mineral hydroxyapatite, Ca₅(PO₄)₃OH (502.31 g/mol per formula unit), incorporates hydroxide ions into a more complex crystal lattice.

Stable indefinitely as a dry solid under normal storage conditions. Keep away from strong acids, which will dissolve it, and from prolonged moisture exposure in food-grade applications to prevent caking.

Low toxicity; treat as a nuisance dust. Use standard dust masks and eye protection when handling large quantities of fine powder to avoid respiratory or eye irritation.

Generally recognized as safe for food and pharmaceutical use; fine powder may cause mild respiratory or eye irritation.

• Mild respiratory irritation from inhaled fine powder
• Eye irritation from dust contact
• No significant acute toxicity at typical exposure levels

Classification: Not classified as hazardous under GHS for food/pharmaceutical-grade material

1. 1. Calculate the molar mass of Ca₃(PO₄)₂.

   Show answer

   3(40.08) + 2[30.97 + 4(16.00)] = 120.24 + 189.94 = 310.18 g/mol

2. 2. How many moles of Ca²⁺ are in 62.04 g of Ca₃(PO₄)₂?

   Show answer

   62.04 g ÷ 310.18 g/mol = 0.200 mol Ca₃(PO₄)₂ → 0.200 × 3 = 0.600 mol Ca²⁺

3. 3. What mass of H₃PO₄ is needed to fully dissolve 31.0 g of Ca₃(PO₄)₂ via HCl reaction stoichiometry (producing H₃PO₄)?

   Hint: Each mole of Ca₃(PO₄)₂ yields 2 mol H₃PO₄ upon complete acid dissolution.

   Show answer

   31.0 g ÷ 310.18 g/mol = 0.100 mol Ca₃(PO₄)₂ → 0.200 mol H₃PO₄ produced × 98.00 g/mol = 19.6 g

4. 4. Why is calcium phosphate insoluble in water but soluble in acid?

   Show answer

   Acid protonates the phosphate anion, disrupting the ionic lattice and forming soluble phosphoric acid species and free calcium ions.

• Phosphoric AcidH₃PO₄

The sections above give the number you need for calculations. Here we look more closely at how Calcium Phosphate (Ca₃(PO₄)₂) behaves chemically—so the molar mass connects to real reactions, properties, and laboratory practice.

Calcium phosphate (Ca₃(PO₄)₂) is an ionic compound with molar mass 310.18 g/mol (Ca 3 × 40.08 + P 2 × 30.97 + O 8 × 16.00), composed of three Ca²⁺ ions balancing two PO₄³⁻ ions. As the simplified "tricalcium phosphate" formula, it represents the basic calcium-to-phosphate stoichiometry found throughout biological mineralization, even though the actual mineral phase in bone and teeth is the more complex, hydroxide-containing compound hydroxyapatite, Ca₅(PO₄)₃OH (or more precisely Ca₁₀(PO₄)₆(OH)₂).

Roughly 99% of the body's calcium and 85% of its phosphorus reside in the skeleton and teeth as this calcium phosphate mineral phase, deposited onto a collagen protein scaffold to give bone its combination of rigidity and slight flexibility — a natural composite material that chemists and materials scientists have long tried to replicate synthetically for bone grafts and dental implant coatings. The same fundamental Ca:P chemistry that builds skeletons also governs the global fertilizer industry, since rock phosphate (largely calcium phosphate minerals like fluorapatite) is the essential raw material converted into superphosphate and other soluble phosphate fertilizers that sustain modern agriculture.

Beyond biology and agriculture, calcium phosphate serves as a food additive (anticaking agent, calcium fortification, leavening acid component), a component of bone china and specialty ceramics, and — significant in molecular biology — as the classic calcium phosphate co-precipitation method used for decades to transfect DNA into cultured mammalian cells, exploiting the tendency of calcium and phosphate ions to co-precipitate around nucleic acid molecules under controlled conditions.

Ca₃(PO₄)₂ balances three Ca²⁺ ions (total charge +6) against two PO₄³⁻ ions (total charge −6). Each phosphate ion is a tetrahedral anion with phosphorus in the +5 oxidation state at the center of four oxygen atoms. This simplified formula represents the idealized calcium orthophosphate stoichiometry, distinct from the hydroxide-containing hydroxyapatite that actually mineralizes bone and tooth enamel.

Ca₃(PO₄)₂ is insoluble in neutral or basic water but dissolves readily in acids, since phosphate is the conjugate base of the weak triprotic phosphoric acid and readily accepts protons. It reacts with sulfuric acid industrially to release soluble monocalcium phosphate and phosphoric acid (the basis of superphosphate fertilizer manufacture), and it can be converted to the biologically relevant hydroxyapatite phase by reaction with hydroxide-containing solutions under physiological-like conditions.

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• PubChem CID 24456: Tricalcium phosphate compound data
• USGS: Phosphate rock mining and reserve statistics
• NIST Chemistry WebBook: Thermodynamic properties