Calcium cyanamide

Calcium cyanamide or CaCN2 is a calcium compound used as fertiliser, first synthesized in 1898 by Adolph Frank and Nikodem Caro. It is formed when calcium carbide reacts with nitrogen. It is commercially known as Nitrolim


 * 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 crystalizes in hexagonal crystal system with space group R3m and lattice constants a = 3.67, c = 14.85 (.10-1 nm).

Uses
The main use of calcium cyanamide is in agriculture as a fertiliser. 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