[Cr(NH3)6]3+ is paramagnetic while [Ni(CN)4]2– is diamagnetic. Explain why?
Overall charge balance in [Cr(NH3)6]3+ complex:
X + 6(0) = + 3
X = + 3
Cr is in + 3 oxidation state.
Electronic configuration of Cr in + 2 state: 3d3 . Now ammonia is a weak field ligand so it not causes pairing of the unpaired electron and undergoes hybridisation to form 6 sp3d2 hybrid orbitals filled by the six ammonia ligands. It's geometry is octahedral with unpaired electrons and hence is paramagnetic complex.
In case of [Ni(CN)4]2– ion :
Overall charge balance in [Ni(CN)4]2–complex:
X + 4(-1) = -2
X = + 2
Ni is in + 2 oxidation state.
Electronic configuration of Ni in + 2 state: 3d8. Now cyanide ion is a strong field ligand so it causes pairing of the unpaired electron and undergoes hybridisation to form 4 dsp2 hybrid orbitals filled by the four cyanide ligands. It's geometry is square planar with no unpaired electrons and hence is diamagnetic complex.
Using IUPAC norms write the formulas for the following:
(i) Tetrahydroxidozincate (II)
(ii) Potassium tetrachloridopalladate (II)
(iii) Diamminedichloridoplatinum (II)
(iv) Potassium tetracyanidonickelate (II)
(v) Pentaamminenitrito-O-cobalt (III)
(vi) Hexaamminecobalt (III) sulphate
(vii) Potassium tri (oxalato) chromate (III)
(viii) Hexaammineplatinum (IV)
(ix) Tetrabromidocuprate (II)
(x) Pentaamminenitrito-N-cobalt (III)
Write down the IUPAC name for each of the following complexes and indicate the oxidation state, electronic configuration and coordination number. Also give stereochemistry and magnetic moment of the complex:
(i) K[Cr(H2O)2(C2O4)2].3H2O (iii) [CrCl3(py)3] (v) K4[Mn(CN)6]
(ii) [Co(NH3)5Cl-]Cl2 (iv) Cs[FeCl4]