Q28E - Chemistry (OpenStax)

Question

Give the coordination number for each metal ion in the following compounds:

\(\begin{aligned}{\underline{\phantom{xx}}}(a){\left( {Co{{\left( {C{O_3}} \right)}_3}} \right)^{3 - }}\\(b){\left( {Cu{{\left( {N{H_3}} \right)}_4}} \right)^{2 + }}\\(c){\left( {Co{{\left( {N{H_3}} \right)}_4}B{r_2}} \right)_2}{\left( {S{O_4}} \right)_3}\\(d)\left( {Pt{{\left( {N{H_3}} \right)}_4}} \right)\left( {PtC{l_4}} \right)\\(e)\left( {Cr{{(en)}_3}} \right){\left( {N{O_3}} \right)_3}\\(f)\left( {Pd{{\left( {N{H_3}} \right)}_2}B{r_2}} \right)\\(g){K_3}\left( {Cu{{(Cl)}_5}} \right)\\(h)\left( {Zn{{\left( {N{H_3}} \right)}_2}C{l_2}} \right)\end{aligned}\)

Step-by-Step Solution

Answer

The number of ligands attached to the central metal ion present inside the coordination sphere is called coordination number of central metal ion.These are attached through the secondary valencies.

Explanation

a)

• In\( {\left( {Co{{\left( {C{O_3}} \right)}_3}} \right)^{3 - }}\), we can see that \(3\)bidentate ligands are present inside the coordination sphere, which idicates the coordination number of the central metal ion \(Co\) is \(6\).

(b)

• In\({\left( {Cu{{\left( {N{H_3}} \right)}_4}} \right)^{2 + }}\), We can see that \(4\) monodentate ligands are present inside the coordination sphere, which means the coordination number of the central metal ion \(Cu\) is \(4\).

(c)

• In \({\left( {Co{{\left( {N{H_3}} \right)}_4}B{r_2}} \right)_2}{\left( {S{O_4}} \right)_3}\), We can see that \(6\)monodentate ligands are present inside the coordination sphere, which means the coordination number of the central metal ion \(Co\)is \(6\).

(d)

• In\(\left( {Pt{{\left( {N{H_3}} \right)}_4}} \right)\left( {PtC{l_4}} \right)\), We can see that \(4\) monodentate ligands are present inside the coordination sphere, in both cases, which means the coordination number of the central metal ion \(Pt\) is \(4\) .

(e)

• In\(\left( {Cr{{(en)}_3}} \right){\left( {N{O_3}} \right)_3}\), We can see that \(3\)bidentate ligands are present inside the coordination sphere, which means the coordination number of the central metal ion \({\rm{Cr}}\)is \(6\).

(f)

• In \(\left( {Pd{{\left( {N{H_3}} \right)}_2}B{r_2}} \right)\), We can see that \(4\) monodentate ligands are present inside the coordination sphere, which means the coordination number of the central metal ion \(Pd\) is \(4\)

(g)

• In\({K_3}\left( {Cu{{(Cl)}_5}} \right)\), We can see that \(5\) monodentate ligands are present inside the coordination sphere, which means the coordination number of the central metal ion \(Cu\) is \(5\). 

(h)

• In\(\left( {Zn{{\left( {N{H_3}} \right)}_2}C{l_2}} \right)\), We can see that \(4\)monodentate ligands are present inside the coordination sphere, which means the coordination number of the central metal ion \({\rm{Zn}}\)is \(4\).

Result

\(\begin{aligned}{\underline{\phantom{xx}}}a){\rm{Co}} &= 6\\b){\rm{Cu}} &= 4\\c){\rm{Co}} &= 6\\d)P{\rm{t}} &= 4\\e){\rm{Cr}} &= 6\\f)Pd &= 4\\g){\rm{Cu}} &= 5\\h)Zn &= 4\end{aligned}\)