Question

Give the oxidation state, d-orbital occupation and coordination number of the central metal ion in the following complexes:
(i) $K_3[Co(C_2O_4)_3]$
(ii)$cis-[Cr(en)_2Cl_2]Cl$
(iii) $(NH_4)_2[CoF_4]$
(iv) $[Mn(H_2O)_6]SO_4$

Answer 1

(i) $K_3[Co(C_2O_4)_3]$
The central metal ion is $Co.$
Its coordination number is $6$.
The oxidation state can be given as:
$x-6 =-3$
$x =+3$
The d orbital occupation for$Co^{ 3+}$ is $t_{2g}^{ 6}e_g^{0}.$

(ii) $cis-[Cr(en)_2Cl_2]Cl$
The central metal ion is $Cr.$
The coordination number is $6.$
The oxidation state can be given as:
$x+2(0)+2(-1)=+1$
$x - 2 = +1$
$x = +3$
The d orbital occupation for $Cr^{3+}$ is $t_{2g}^{3} .$

(iii) $(NH_4)_2[CoF_4]$ The central metal ion is$Co.$
The coordination number is $4.$
The oxidation state can be given as:
$x-4 =-2$
$x=+2$ The d orbital occupation for $Co^{2+}$is $e_g^{4}\space t_{2g} ^{3}.$

(iv) $[Mn(H_2O)_6]SO_4$The central metal ion is $Mn.$
The coordination number is $6$.
The oxidation state can be given as:
$x+0=+2$
$x=+2$ The d orbital occupation for $Mn$ is $t_{2g}^{3}\space e_g^{2} .$