Write the formula for a complex formed between co3+ and nh3, with a coordination of 6

The complex formed between Co3+ and NH3 is [Co(NH3)6]^3+ and is called Hexaminecobalt(III).

Explanation:

The first step in the syntheses of these complexes requires oxidation to convert the metal from the +2 to the +3 oxidation  state

2Co2+ → 2Co3+ + 2e-

2Co3+ + 12NH3 → 2[Co(NH3)6] ^3+

The netto reaction will be:

2Co2+ + H2O2(aq)+ 12NH3 → 2 [Co(NH3)6] ^3+ + 2OH-

Hydrogen  peroxide as an oxidizing agent generates only OH– as reduced product, and the presence of ammonia guarantees that  the Co3+ will be stabilized immediately by formation of amine component.

The complex formed between Co3+ and NH3 is [Co(NH3)6]^3+ and is called Hexaminecobalt(III).

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