Classification
Compound
Free cyanide
CN−, HCN
Simple compounds
a) readily soluble
b) neutral insoluble salts
NaCN, KCN, Ca(CN)2, Hg(CN)2, Zn(CN)2, Cd(CN)2, CuCN, Ni(CN)2, AgCN
Weak complexes
, 
, 
Moderately strong complexes
, 
, 
, 
Strong complexes
, 
, 
, 