Calcium cyanamide

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Calcium cyanamide
Calcium cyanamide.jpg
Freshly made calcium cyanamide
IUPAC name
Calcium cyanamide
Other names
Cyanamide calcium salt
Lime Nitrogen
UN 1403
Molar mass 80.102 g/mol
Appearance White solid (Often gray or black from impurities)
Odor Odorless
Density 2.29 g/cm3
Melting point 1,340 °C (2,440 °F; 1,610 K)
Boiling point Sublimes
Solubility Reacts with acids
Insoluble in organic solvents
Vapor pressure ~0 mmHg
-351.6 kJ/mol
Safety data sheet Sigma-Aldrich
Flash point Non-flammable
Related compounds
Related compounds
Calcium carbide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Calcium cyanamide is an inorganic compound with the formula CaCN2, widely used as fertilizer in agriculture.



Hydrolysis of CaCN2 will yield cyanamide, as well as ammonia.

CaCN2 + H2O + CO2 → CaCO3 + H2NCN
CaCN2 + 3 H2O → 2 NH3 + CaCO3

Fusing calcium cyanamide with sodium carbonate will give sodium cyanide.

CaCN2 + Na2CO3 + 2C → 2 NaCN + CaO + 2 CO

Fusing calcium cyanamide with ammonium nitrate at high temperatures will give guanidinium nitrate.[2] Although some old literature data indicates that the reaction can also be done in an aq. solution, it's been shown that the presence of water may lead to the formation of other side products.[3]


Calcium cyanamide is a white (gray or black if impure) solid, which reacts with water.


Calcium cyanamide is sold as fertilizer. In some places it's hard to find, as the compounds readily hydrolyzes in the presence of moisture, and water-sensitive materials are generally not sold in most stores due to safety.

It can also be bought from chemical suppliers.


A common route to calcium cyanamide involves heating a mixture of calcium oxide and urea at 120-350 °C which gives calcium cyanate, followed by calcination at 7-900 °C to give calcium cyanamide.[4]

3 CO(NH2)2 → 3 HOCN + NH3
CaO + 2 HOCN → Ca(OCN)2 + H2O
Ca(OCN)2 → CaCN2 + CO2

Calcium cyanamide is obtained industrially by heating calcium carbide powder at 1,000 °C, usually in an electric furnace, while injecting nitrogen gas over the hot carbide, which is recirculated. The reaction takes several hours for completion. The reaction produces carbon and is the reason commercial calcium cyanamide fertilizer is usually black in color.

CaC2 + N2 → Ca(CN)2 → CaCN2 + C

Another route involves heating calcium cyanide with nitrogen gas at 600 °C for at least one hour.[5]

Reducing calcium nitride with carbon at 800-900 °C in a nitrogen atmosphere will also give calcium cyanamide.[6]

Reacting ammonia with calcium carbonate above 600 °C is another route.[7][8]

Since calcium cyanamide reacts with oxygen at high temperatures, all of these routes must be done in the absence of oxygen, thus an inert gas is often used.




Calcium cyanamide is harmful and should be handled with care.

It is known to cause alcohol intolerance, before or after the consumption of alcohol.


Calcium cyanamide must be kept in closed containers, away from moisture. Empty paint or instant coffee cans are good.


Can be dumped in the ground.



  1. Franck, H. H.; Hochwald, F.; Zeitschrift fuer Elektrochemie; vol. 31; (1925); p. 581 - 590
  5. Franck, H.; Heimann, H.; Angewandte Chemie; vol. 44; (1931); p. 372 - 378
  6. Krase, H. J.; Jee, J. Y.; Journal of the American Chemical Society; vol. 46; (1924); p. 1358 - 1366
  7. Franklin; Journal of the American Chemical Society; vol. 44; (1922); p. 504
  8. Patent; Caro; Frank; DE467479; Fortschr. Teerfarbenfabr. Verw. Industriezweige; vol. 16; p. 283

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