Calcium cyanamide

Calcium cyanamide
Calcium cyanamide
Identifiers
CAS number 156-62-7 YesY
PubChem 4685067
ChemSpider 10669887 YesY
UNII ZLR270912W YesY
EC number 205-861-8
UN number 1403
RTECS number GS6000000
Jmol-3D images Image 1
Properties
Molecular formula CaCN2
Molar mass 80.102 g/mol
Appearance White solid (Often gray or black from impurities)
Odor odorless
Density 2.29 g/cm3
Melting point

1340 °C [1]

Boiling point

1150-1200 °C (sublim.)

Solubility in water Reacts
Hazards
MSDS ICSC 1639
EU Index 615-017-00-4
EU classification Harmful (Xn)
Irritant (Xi)
R-phrases R22 R37 R41
S-phrases (S2) S22 S26 S36/37/39
NFPA 704
NFPA 704.svg
0
3
1
W
Flash point Non-flammable
Related compounds
Related compounds Cyanamide
Calcium carbide
 YesY cyanamide (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Calcium cyanamide or CaCN2 is a calcium compound used as fertilizer,[2] first synthesized in 1898 by Adolph Frank and Nikodem Caro (Frank-Caro process).[3] It is formed when calcium carbide reacts with nitrogen. It is commercially known as Nitrolime.

CaC2 + N2 → CaCN2 + C

The reaction takes place in large steel chambers. An electric carbon element heats the reactants to red heat. Nitrogen is pressurised at 2 atmospheres.

It crystallizes in hexagonal crystal system with space group R3m and lattice constants a = 3.67, c = 14.85 (.10−1 nm).[4]

Contents

Preparation

Calcium cyanamide is prepared from calcium carbide. The carbide powder is heated at about 1,000°C in an electric furnace into which nitrogen is passed for several hours. The product is cooled to ambient temperatures and any unreacted carbide is leached out cautiously with water.

CaC2 + N2 → CaCN2 + C (ΔHƒ°= –69.0 kcal/mol at 25°C)

Uses

The main use of calcium cyanamide is in agriculture as a fertilizer.[2] In contact with water it decomposes and liberates ammonia:

CaCN2 + 3 H2O → 2 NH3 + CaCO3

It was used to produce sodium cyanide by fusing with sodium carbonate, which was used in cyanide process in gold mining:

CaCN2 + Na2CO3 → 2 NaCN + CaO + O2

It can also be used in the preparation of calcium cyanide and melamine.

Through hydrolysis, calcium cyanamide produces cyanamide.

CaCN2 + H2O + CO2 → CaCO3 + H2NCN

The conversion is conducted on slurries, consequently most commercial cyanamide is sold as an aqueous solution.

Thiourea can be produced by the reaction of hydrogen sulfide with calcium cyanamide in the presence of carbon dioxide.[5]

Calcium cyanamide is also used as a wire-fed alloy in steelmaking, in order to introduce nitrogen into the steel.

See also

References

  1. ^ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0070494398
  2. ^ a b Auchmoody, L.R.; Wendel, G.W. (1973). "Effect of calcium cyanamide on growth and nutrition of plan fed yellow-poplar seedlings". U.S. Department of Agriculture, Forest Service. http://www.treesearch.fs.fed.us/pubs/23629. Retrieved 2008-07-18. 
  3. ^ "History of Degussa: Rich harvest, healthy environment". http://www.degussa-history.com/geschichte/en/inventions/calcium_cyanamide/. Retrieved 2008-07-18. 
  4. ^ F. Brezina, J. Mollin, R. Pastorek, Z. Sindelar. Chemicke tabulky anorganickych sloucenin (Chemical tables of inorganic compounds). SNTL, 1986.
  5. ^ Bernd Mertschenk, Ferdinand Beck, Wolfgang Bauer "Thiourea and Thiourea Derivatives" in Ullmann's Encyclopedia of Industrial Chemistry 2002 by Wiley-VCH Verlag GmbH & Co. KGaA. All rights reserved. DOI: 10.1002/14356007.a26_803

External links


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Look at other dictionaries:

  • calcium cyanamide — n. a white, crystalline compound, CaCN2, used as a fertilizer, weed killer, etc …   English World dictionary

  • calcium cyanamide — noun also calcium cyanamid : a compound CaCN2 obtained in impure cokelike form by passing dry nitrogen over calcium carbide at about 1100° C and used chiefly as a fertilizer, as a weed killer, in the defoliation of crops (as cotton), and as a… …   Useful english dictionary

  • calcium cyanamide — a compound, CaCN2, which inhibits one or more of the enzymes required for oxidation of acetaldehyde formed from alcohol; used as a fertilizer, defoliant, herbicide, and pesticide. Drinking of alcohol after inhalation or ingestion of calcium… …   Medical dictionary

  • calcium cyanamide — kalcio cianamidas statusas T sritis chemija apibrėžtis Kalcio azoto trąša. formulė CaCN₂ atitikmenys: angl. calcium cyanamide; nitrolim; nitrolime rus. цианамид кальция …   Chemijos terminų aiškinamasis žodynas

  • calcium cyanamide — a gray black, often lumpy powder, CaCN2, unstable in water, obtained by heating calcium carbide and nitrogen; cyanamide: used chiefly as a fertilizer, herbicide, and intermediate in the synthesis of nitrogen compounds. [1905 10] * * * …   Universalium

  • calcium-cyanamide — noun a compound used as a fertilizer and as a source of nitrogen compounds • Syn: ↑cyanamide • Hypernyms: ↑compound, ↑chemical compound …   Useful english dictionary

  • calcium cyanamide — noun Date: circa 1893 a compound CaCN2 used as a fertilizer and a weed killer and as a source of other nitrogen compounds …   New Collegiate Dictionary

  • calcium cyanamide — CaCN3, used in aquaculture as a pond disinfectant, especially for Myxosoma cerebralis, the cause of whirling disease. Also called lime nitrogen …   Dictionary of ichthyology

  • calcium cyanamide — cal′cium cyan′amide n. chem. a gray black powder, CaCN2, used as a fertilizer and herbicide • Etymology: 1905–10 …   From formal English to slang

  • Cyanamide process — is a process of manufacturing fertilizer calcium cyanamide and ammonia. The reaction runs at high temperatures 1000 1100 °C often with catalyst in mixture of nitrogen and calcium carbide, which form calcium cyanamide and carbon: CaC2 + N2 → CaCN2 …   Wikipedia

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