1. Complex Ion Formation

2. Formation
Transition metal ions such as Cu+2 , Ag+, and Ni+ react with excess ligands to form coordination complexes.
Examples of ligands
OH- , (hydroxo)
CN- , (cyano)
NH3, (amine)
H+, (halo (halides))

3. Sometimes, # ligands = 2(Charge of transition metal ion)
Charge on complex ion = total charge of all ligands + TM ion.

4. Sample problem:
Solid zinc nitrate is treated with excess sodium hydroxide solution.
Zn(NO3)2(s) + 4OH-(aq)  Zn(OH) NO3-(aq)
What is the charge of the zinc ion?