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3Ca(CN)2 + 3Na2HPO4 💧→ Ca3(PO4)2↓ + 6NaCN + H3PO4

3Ca(CN)₂ + 3Na₂HPO₄ 💧→ Ca₃(PO₄)₂↓ + 6NaCN + H₃PO₄

Last updated: June 13, 2022

Reaction of calcium cyanide and sodium hydrogenphosphate: 3Ca(CN)₂Calcium cyanide + 3Na₂HPO₄Sodium hydrogenphosphate
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Ca₃(PO₄)₂↓Calcium phosphate + 6NaCNSodium cyanide + H₃PO₄Phosphoric acid

The reaction of calcium cyanide and sodium hydrogenphosphate yields calcium phosphate, sodium cyanide, and phosphoric acid (Other reactions are here). This reaction is an acid-base reaction and is classified as follows:

Precipitation reaction

Table of contents

Reaction data

Chemical equation

Reaction of calcium cyanide and sodium hydrogenphosphate: 3Ca(CN)₂Calcium cyanide + 3Na₂HPO₄Sodium hydrogenphosphate
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Ca₃(PO₄)₂↓Calcium phosphate + 6NaCNSodium cyanide + H₃PO₄Phosphoric acid

General equation

Precipitation reaction: Miscible with water/Very soluble in water/Soluble in waterLewis acid + Miscible with water/Very soluble in water/Soluble in waterLewis base
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Insoluble in water/Very slightly soluble in water/Slightly soluble in waterLewis conjugate + Product(Non-redox product)

Oxidation state of each atom

Reaction of calcium cyanide and sodium hydrogenphosphate

Reactants

Chemical formula	Name	Coefficient	Type	Type in general equation
Ca(CN)₂	Calcium cyanide	3	Lewis acid	Soluble in water
Na₂HPO₄	Sodium hydrogenphosphate	3	Lewis base	Soluble in water

Products

Chemical formula	Name	Coefficient	Type	Type in general equation
Ca₃(PO₄)₂	Calcium phosphate	1	Lewis conjugate	Very slightly soluble in water
NaCN	Sodium cyanide	6	Non-redox product	–
H₃PO₄	Phosphoric acid	1	Non-redox product	–

Thermodynamic changes

Changes in standard condition (1)

Reaction of calcium cyanide and sodium hydrogenphosphate: 3Ca(CN)₂Crystalline solid + 3Na₂HPO₄Crystalline solid
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Ca₃(PO₄)₂↓Crystalline solidβ, low temp. form + 6NaCNCrystalline solidcubic + H₃PO₄Crystalline solid

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	−126.9	–	–	–
per 1 mol of Calcium cyanide	−42.30	–	–	–
per 1 mol of Sodium hydrogenphosphate	−42.30	–	–	–
per 1 mol of Calcium phosphate	−126.9	–	–	–
per 1 mol of Sodium cyanide	−21.15	–	–	–
per 1 mol of Phosphoric acid	−126.9	–	–	–

Changes in standard condition (2)

Reaction of calcium cyanide and sodium hydrogenphosphate: 3Ca(CN)₂Crystalline solid + 3Na₂HPO₄Crystalline solid
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Ca₃(PO₄)₂↓Crystalline solidβ, low temp. form + 6NaCNCrystalline solidorthorhombic + H₃PO₄Crystalline solid

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	−146.5	–	–	–
per 1 mol of Calcium cyanide	−48.83	–	–	–
per 1 mol of Sodium hydrogenphosphate	−48.83	–	–	–
per 1 mol of Calcium phosphate	−146.5	–	–	–
per 1 mol of Sodium cyanide	−24.42	–	–	–
per 1 mol of Phosphoric acid	−146.5	–	–	–

Changes in standard condition (3)

Reaction of calcium cyanide and sodium hydrogenphosphate: 3Ca(CN)₂Crystalline solid + 3Na₂HPO₄Crystalline solid
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Ca₃(PO₄)₂↓Crystalline solidα, high temp. form + 6NaCNCrystalline solidcubic + H₃PO₄Crystalline solid

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	−116.0	–	–	–
per 1 mol of Calcium cyanide	−38.67	–	–	–
per 1 mol of Sodium hydrogenphosphate	−38.67	–	–	–
per 1 mol of Calcium phosphate	−116.0	–	–	–
per 1 mol of Sodium cyanide	−19.33	–	–	–
per 1 mol of Phosphoric acid	−116.0	–	–	–

Changes in standard condition (4)

Reaction of calcium cyanide and sodium hydrogenphosphate: 3Ca(CN)₂Crystalline solid + 3Na₂HPO₄Crystalline solid
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⟶
Ca₃(PO₄)₂↓Crystalline solidα, high temp. form + 6NaCNCrystalline solidorthorhombic + H₃PO₄Crystalline solid

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	−135.6	–	–	–
per 1 mol of Calcium cyanide	−45.20	–	–	–
per 1 mol of Sodium hydrogenphosphate	−45.20	–	–	–
per 1 mol of Calcium phosphate	−135.6	–	–	–
per 1 mol of Sodium cyanide	−22.60	–	–	–
per 1 mol of Phosphoric acid	−135.6	–	–	–

Changes in aqueous solution (1)

Reaction of calcium cyanide and sodium hydrogenphosphate: 3Ca(CN)₂Aqueous solution + 3Na₂HPO₄Ionized aqueous solution
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Ca₃(PO₄)₂↓Crystalline solidβ, low temp. form + 6NaCNIonized aqueous solution + H₃PO₄Un-ionized aqueous solution

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	85.3	–	–	–
per 1 mol of Calcium cyanide	28.4	–	–	–
per 1 mol of Sodium hydrogenphosphate	28.4	–	–	–
per 1 mol of Calcium phosphate	85.3	–	–	–
per 1 mol of Sodium cyanide	14.2	–	–	–
per 1 mol of Phosphoric acid	85.3	–	–	–

Changes in aqueous solution (2)

Reaction of calcium cyanide and sodium hydrogenphosphate: 3Ca(CN)₂Aqueous solution + 3Na₂HPO₄Ionized aqueous solution
💧
⟶
Ca₃(PO₄)₂↓Crystalline solidβ, low temp. form + 6NaCNIonized aqueous solution + H₃PO₄Un-ionized aqueous solution

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	85.3	–	–	–
per 1 mol of Calcium cyanide	28.4	–	–	–
per 1 mol of Sodium hydrogenphosphate	28.4	–	–	–
per 1 mol of Calcium phosphate	85.3	–	–	–
per 1 mol of Sodium cyanide	14.2	–	–	–
per 1 mol of Phosphoric acid	85.3	–	–	–

Changes in aqueous solution (3)

Reaction of calcium cyanide and sodium hydrogenphosphate: 3Ca(CN)₂Aqueous solution + 3Na₂HPO₄Ionized aqueous solution
💧
⟶
Ca₃(PO₄)₂↓Crystalline solidα, high temp. form + 6NaCNIonized aqueous solution + H₃PO₄Un-ionized aqueous solution

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	96.2	–	–	–
per 1 mol of Calcium cyanide	32.1	–	–	–
per 1 mol of Sodium hydrogenphosphate	32.1	–	–	–
per 1 mol of Calcium phosphate	96.2	–	–	–
per 1 mol of Sodium cyanide	16.0	–	–	–
per 1 mol of Phosphoric acid	96.2	–	–	–

Changes in aqueous solution (4)

Reaction of calcium cyanide and sodium hydrogenphosphate: 3Ca(CN)₂Aqueous solution + 3Na₂HPO₄Ionized aqueous solution
💧
⟶
Ca₃(PO₄)₂↓Crystalline solidα, high temp. form + 6NaCNIonized aqueous solution + H₃PO₄Un-ionized aqueous solution

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	96.2	–	–	–
per 1 mol of Calcium cyanide	32.1	–	–	–
per 1 mol of Sodium hydrogenphosphate	32.1	–	–	–
per 1 mol of Calcium phosphate	96.2	–	–	–
per 1 mol of Sodium cyanide	16.0	–	–	–
per 1 mol of Phosphoric acid	96.2	–	–	–

Changes in aqueous solution (5)

Reaction of calcium cyanide and sodium hydrogenphosphate: 3Ca(CN)₂Aqueous solution + 3Na₂HPO₄Ionized aqueous solution
💧
⟶
Ca₃(PO₄)₂↓Crystalline solidβ, low temp. form + 6NaCNIonized aqueous solution + H₃PO₄Ionized aqueous solution

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	96.2	–	–	–
per 1 mol of Calcium cyanide	32.1	–	–	–
per 1 mol of Sodium hydrogenphosphate	32.1	–	–	–
per 1 mol of Calcium phosphate	96.2	–	–	–
per 1 mol of Sodium cyanide	16.0	–	–	–
per 1 mol of Phosphoric acid	96.2	–	–	–

Changes in aqueous solution (6)

Reaction of calcium cyanide and sodium hydrogenphosphate: 3Ca(CN)₂Aqueous solution + 3Na₂HPO₄Ionized aqueous solution
💧
⟶
Ca₃(PO₄)₂↓Crystalline solidα, high temp. form + 6NaCNIonized aqueous solution + H₃PO₄Ionized aqueous solution

	Standard enthalpy of reaction Δ_rH° kJ · mol⁻¹	Standard Gibbs energy of reaction Δ_rG° kJ · mol⁻¹	Standard entropy of reaction Δ_rS° J · K⁻¹ · mol⁻¹	Standard heat capacity of reaction at constant pressure Δ_rC_p° J · K⁻¹ · mol⁻¹
per 1 mol of Equation	107.1	–	–	–
per 1 mol of Calcium cyanide	35.70	–	–	–
per 1 mol of Sodium hydrogenphosphate	35.70	–	–	–
per 1 mol of Calcium phosphate	107.1	–	–	–
per 1 mol of Sodium cyanide	17.85	–	–	–
per 1 mol of Phosphoric acid	107.1	–	–	–

Thermodynamic data of reactants

Chemical formula	Standard enthalpy of formation Δ_fH° kJ · mol⁻¹	Standard Gibbs energy of formation Δ_fG° kJ · mol⁻¹	Standard molar entropy S° J · K⁻¹ · mol⁻¹	Standard molar heat capacity at constant pressure C_p° J · K⁻¹ · mol⁻¹
Ca(CN)₂ (cr)	-184.5^[1]	–	–	–
Ca(CN)₂ (aq)	-238.1^[1]	–	–	–
Na₂HPO₄ (cr)	-1748.1^[1]	-1608.2^[1]	150.50^[1]	135.31^[1]
Na₂HPO₄ (ai)	-1772.38^[1]	-1612.98^[1]	84.5^[1]	–
Na₂HPO₄ (cr) 2 hydrate	-2346.0^[1]	-2088.5^[1]	221.3^[1]	–
Na₂HPO₄ (cr) 7 hydrate	-3821.7^[1]	-3279.8^[1]	434.59^[1]	–
Na₂HPO₄ (cr) 12 hydrate	-5297.8^[1]	-4467.8^[1]	633.83^[1]	–

* (cr):Crystalline solid, (aq):Aqueous solution, (ai):Ionized aqueous solution

Thermodynamic data of products

Chemical formula	Standard enthalpy of formation Δ_fH° kJ · mol⁻¹	Standard Gibbs energy of formation Δ_fG° kJ · mol⁻¹	Standard molar entropy S° J · K⁻¹ · mol⁻¹	Standard molar heat capacity at constant pressure C_p° J · K⁻¹ · mol⁻¹
Ca₃(PO₄)₂ (cr) β, low temp. form	-4120.8^[1]	-3884.7^[1]	236.0^[1]	227.82^[1]
Ca₃(PO₄)₂ (cr) α, high temp. form	-4109.9^[1]	-3875.5^[1]	240.91^[1]	231.58^[1]
Ca₃(PO₄)₂ (ai)	-4183.2^[1]	-3698.1^[1]	-599.9^[1]	–
NaCN (cr) cubic	-87.49^[1]	-76.43^[1]	115.60^[1]	70.37^[1]
NaCN (cr) orthorhombic	-90.75^[1]	–	–	–
NaCN (g)	109^[1]	79.94^[1]	249.43^[1]	51.17^[1]
NaCN (ai)	-89.5^[1]	-89.5^[1]	153.1^[1]	–
NaCN (cr) 1/2 hydrate	-235.77^[1]	–	–	–
NaCN (cr) 2 hydrate	-679.77^[1]	–	–	–
H₃PO₄ (cr)	-1279.0^[1]	-1119.1^[1]	110.50^[1]	106.06^[1]
H₃PO₄ (l)	-1266.9^[1]	–	–	–
H₃PO₄ (ai)	-1277.4^[1]	-1018.7^[1]	-220.3^[1]	–
H₃PO₄ (ao)	-1288.34^[1]	-1142.54^[1]	158.2^[1]	–
H₃PO₄ (cr) 0.5 hydrate	-1431.3^[1]	-1242.1^[1]	129.16^[1]	126.02^[1]
H₃PO₄ (cr) 1 hydrate	-1568.83^[1]	–	–	–

* (cr):Crystalline solid, (ai):Ionized aqueous solution, (g):Gas, (l):Liquid, (ao):Un-ionized aqueous solution

References

List of references

1
Janiel J. Reed (1989)
The NBS Tables of Chemical Thermodynamic Properties: Selected Values for Inorganic and C1 and C2 Organic Substances in SI Units
https://doi.org/10.18434/M32124
National Institute of Standards and Technology (NIST)
Citation list