Calcium Cyanamide


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calcium cyanamide

[′kal·sē·əm sī′an·ə‚mīd]
(inorganic chemistry)
CaCN2In pure form, colorless rhombohedral crystals, the commercial form being a gray material containing 55-70% CaCN2; used as a fertilizer, weed killer, and defoliant.

Calcium Cyanamide

 

CaCN2, the calcium salt of cyanamide (H2N—C≡N, the amide of cyanic acid). Calcium cyanam-ide is a colorless crystalline compound that is soluble in water. It has a melting point of ~1300°C.

Technical-grade calcium cyanamide, which is produced by heating calcium carbide in a stream of nitrogen at 1000°C, is a dark gray powder consisting mainly of calcium cyanamide and carbon; the calcium cyanamide content is 57–60 percent. At 1400°–1500°C, technical-grade calcium cyanamide combines with sodium chloride (NaCl) to form cyanide flux, which in the recent past was the major source of hydrocyanic acid and cyanide salts. The salt sodium cyanide was formed by the reaction 2CaCN2 + 2C + 2NaCl ⇄ CaCl2 + Ca(CN)2 + 2NaCN. For a long time calcium cyanamide was used as a raw material in the production of melamine. Calcium cyanamide is toxic.

Calcium cyanamide is a nitrogenous fertilizer, a defoliant, and a herbicide. Fertilizer-grade calcium cyanamide, which has a nitrogen content of 18–22 percent, is effective in acidic and slightly basic soils when applied during autumn plowing. Calcium cyanamide is not used as a fertilizer in the USSR. It is used for the preharvest removal of leaves from cotton plants and for the elimination of shoots of orache, chickweed, daisies, shepherd’s purse, and other weeds from fields planted with grains and certain vegetables.

References in periodicals archive ?
The companies profiled in 2015 Market Research Report on Global Calcium Cyanamide Industry AlzChem, NCI, Denka, Darong Group, Xingping Fine Chemical, Ningxia Sunnyfield, Jiafeng Chemical, Gulang Xinmiao, Yinglite Chemical, Beilite Chemical and Juhua Group.
Effect of calcium cyanamide on pathogenic Escherichia coli during mesophilic composting and impact on composting process, Global Nest Journal 14(4): 460-467.
In new experiments, Weeks wants to determine if outfitting plants with the cah gene would open the door for growers to use calcium cyanamide fertilizer more conveniently; that is, not just on bare soil, but also when plants emerge - or perhaps anytime thereafter - without harming the plants.