Pseudohalides cyanide ion

The kinetics are complex, but the following features are apparent (a) order in Fe(CN)6 between 1 and 2, tending to 1 in presence of Fe(CN)6 (6) first-order retardation by Fe(CN)g (c) order in CN between 1 and 2 (d) rate independent of pH between pH 9 and e) E zero or negative. The following mechanism was proposed  

A complex was detected in these solutions with the composition CuCN but this was not formed in significant quantities under the conditions employed. The role of ammonia molecules could not be assessed, although it was found that the rate showed a strong inverse dependence in ammonia concentration, indicating competition between NHj and CN for coordination sites. 

---