Give the oxidation state, d-orbitals 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)]SO_4`

Explanation

(i) `K_(3)[Co(C_(2)O_(4))_(3)]implies[CO(C_(2)O_(4))_(3)]^(3-).x+3(-2)=-2` Oxidation state `x=+3` coordination
Number is also 6 as `C_(2)O_(4)^(2-)` is distance `Co+3` is a case in which all electrons are paired
(ii) cis- `[Cr(en)2Cl_(2)]+Cl^(-)`
`x+0-2=+1`
Oxidation state `x=+3`
Coordination number is 6 as 'en' is didentate
`Cr^(3+)` is a cfi case, paramagnetic
(iii) `(NH_(4))_(2)[COF_(4)]=(NH_(4))_(2).^(2+)[COF_(4)]^(2-)`
`x-4=-2`
Oxidation state `x=+2`
Coordination number =4
`Co^(2+)` is a `d^(5)` case paramagnetic
(iv) `[Mn(H_(2)O)_(6)]^(2+)SO_(4)^(2-)`
`x+OF+2`
:. Oxidation state `x-+2`
Coordination number is 6
`Mn^(+2)` is a `d^(5)` paramagnetic