[refid]

Hi

i need some clarification on the topic of complex ions: amphoteric and basic hydroxide, and formation of Ammine complex ions.

Thanks

[oldddog]

Complex ions usually refer to cations in which surrounding water molecules have been replaced by some other electron pair donor.

Many cations (Ag⁺, Cu²⁺, Cd²⁺, Zn²⁺, and many others) form complexes with ammonia. These sometimes are called ammine complexes.

Another reaction type frequent seen is the formation of a hydroxide followed by the formation of a soluble hydroxide complex ion. Fe(OH)₃ and Mg(OH)₂ do not form soluble complexes, but aluminum and zinc do:

Zn(OH)₂ + OH^-  -->  Zn(OH)₄^2-

Al(OH)₃ + OH^-  -->  Al(OH)₄^-

[refid]

what would make them  amphoteric??

[refid]

anyone???

[xiankai]

they possess basic and acidic properties