Question

Indicate the coordination number for the central metal atom in each of the following coordination compounds:

a. [Co(NH₃)₄Cl₂]²⁺ - 6
b. [Pt(NH₃)₄]²⁺ - 4
c. [Fe(CN)₆]³⁻ - 6
d. [Cu(H₂O)₄]²⁺ - 4

Answer 1

The coordination number for a metal in a coordination compound is the total number of bonds made between the metal and the ligands. It is determined by counting the number of donor atoms from each ligand that is attached to the central metal atom.

Step-by-step explanation:

The coordination number of the central metal atom in a coordination compound is the number of donor atoms attached to the metal.

This number is determined by counting the ligands that are directly bonded to the central atom, each ligand contributing according to its denticity (the number of bonds it forms with the central atom).

Given the coordination compounds:

• [Co(NH₃)₄Cl₂]²⁺ - The coordination number of Co is 6 as there are 4 ammonia (NH₃) and 2 chloride (Cl) ligands, and each provides one bond to the cobalt, summing up to 6.
• [Pt(NH₃)₄]²⁺ - The coordination number of Pt is 4 because there are 4 ammonia ligands, each binding once to the platinum.
• [Fe(CN)₆]³⁻ - The coordination number of Fe is 6 with 6 cyanide (CN) ligands each forming a single bond with the iron.
• [Cu(H₂O)₄]²⁺ - The coordination number of Cu is 4; it is surrounded by 4 water (H₂O) molecules, each donating a single bond.