Is #"CN"^(-)# a Lewis base? Why?

1 Answer
May 9, 2018

My word....

Explanation:

By definition, a #"Lewis base"# is an electron pair donor..and certainly cyanide anion acts as a ligand in coordination chemistry. Cyanide is isolectronic with #CO#, and while not as #pi-"acidic"# as the carbonyl can accept some electron density from the metal centre.

As a Bronsted base, cyanide salts (and they will not allow undergrads to play with them) will give a slightly basic solution:

#""^(-)C-=N+H_2O(l)rightleftharpoonsHC-=N(aq) + HO^(-)#