Page 1 : 17, Co-ordination Compounds, • Complex salt and double salt, The salt that is obtained according to the laws of chemical combination by combination of two or, more salts (compounds) having independent existence and maintains the properties of the original salts is, called double salt. When (n-1)d, ns and np or ns, np and nd orbitals of the atoms or ions of transition, elements are vacant, these transition elements accept electron pairs from negative ions or neutral, molecules, which are called complex compounds. The differences between double salt and complex salt, are as under :, Double Salt, Complex Salt, (i) The salt that is obtained by combination of two, (i), The salt that is obtained by combination of, or more salts maitains the properties of original, two or more compounds with new properties, salts is called double salt, are called complex salt., |(ii) They exist as crystal and get dissociated when, (ii) They exist as solid or solution even in solution, they are dissolved in water or other solvent., complex ion is not dissociate., (iii) Metal ion possesses their common valency., (iii) Metal ion possesses two types of valency,, primary and secondary., (iv) Double salt lose their properties in solution., (iv) Complex salt do not lose their properties in, solution., (v) Double salt is ionic compound which do not, (v) Complex salt is ionic or nonionic which, possesses co-ordinate bond., possesses co-ordinate bond., Werner theory : Metal ion possesses two types of valency, primary and secondary valency., Primary valency : It is equal to positive charge of metal ion which formed ionic bond and ionisable., Primary valency is satisfied by only negative ions and it is also known as oxidation number of metal., Secondary valency It depends on vacant orbital of metal ion. It is satisfied by negative ion or, neutral molecule which is nonionisable. Secondary valency indicates co-ordination number of metal which, has directional property. Secondary valency of metal is definite, transition metal ion can possess more, than one co-ordination number., Ligand and their classification : Negative ion or neutral molecule which bound to the metal ion by, secondary valency is called as ligand. In complex, metal ion acts as Lewis acid and ligand act as Lewis, base. Ligand are classified according to number of electron pair donating atom in them., Unidentate Ligand The ligand which can from one atom donates one electron pair and form, co-ordinate covalent bond is called unidentate ligand., Didentate Ligand The ligand which can donate two electron pairs to metal ion and form two, co-ordinate covalent bond is called didentate ligand., Polydentate Ligand : The ligand in which two or more co-ordination sites are there or the ligand in, which two or more atoms donate electron pairs to metal ion and form co-ordinate covalent bond is called, polydentate ligand., Polydentate ligand forms cyclic structure with metal ion and form chelate., 431

Page 3 : Didentate Ligand, Name, formula, electric, Name of ligand in, Co-ordination site, charge, complex, Oxalate ion, ОХ OR COО, -2, Oxalato, COO, so,-, |co,2, Sulphate ion, -2, Sulphato, Carbonate ion, Carbonato, Ethane 1, 2-diamine, - CH,, Ethane 1, 2-diamine, N, NH, - NH,, |Glycenate ion, H,N – CH, - C0, Glycenato, N and O, -1, : Ptn, PO,, AsO,*, BO,, -3, -3, -3, Tridentate ligand, Hexadentate ligand, : EDTA, Positive charge ligand, : NO,", NO.", N,H,*, • Stability of complex compound :, As the strength of different ligands to form co-ordinate covalent bond varies, stronger ligand possesses, more attraction with metal ion. As a result complexes having stronger ligand possess more stability. The basis, of strength of ligand can be determined by same metal ion combined with different ligands., • The order of strength of ligand :, CF <F < OH <H,0 < NH, < CN¯, order of stability of complex ion, [NİCIJ- < [NiF,P < [Ni(OH),P < [Ni(H,O),* < [Ni(NH,),*., [Ni(CN),-, CuSO, + 4 NH., 3(ag), → [Cu(NH,)," (ag), + SO 2-, 4 (ag), in the reaction which of the following acts as, 1., Lewis acid ?, (A) NH,, (В) Cu?+, (C) SO,?-, (D) [Cu (NH,),J*, 2., In complex compound ligand is also known as, (A) Lewis acid, (B) Lewis base, (C) Bronsted acid, (D) Bronsted base, 3., How many total ions are formed by ionisation of [Co (NH,)] CI, ?, (A) 9, (В) 3, (С) 4, (D) 6, 4., Which of the following will give white precepitates with complex formed by mixing of aqueous, solution of CuSO, and NH, ?, (A) BaCl,, (B) AgNo,, (С) KI, (D) HCI, 5., What is the co-ordination number and oxidation number of Cr in [Cr (NH,), So] Br ?, (A) 6 and 2, (B) 6 and 3, (С) 4 and 6, (D) 6 and 4, 6., Oxidation state of Ni in [Ni (CO),] is, ... ?, (A) + 2, (В) — 2, (С) 0, (D) 4, 433

Page 4 : 7., In which of following complex, oxidation number of metal ion is zero ?, (A) Fe (CO),, (B) [Ag (NH,),]CI, (C) [Co (NH,)] CI,, (D) K, [Fe (CN),], 8., What is the co-ordination number of metal ion in octahedral complex ?, (A) 4, (В) 2, (С) 5, (D) 6, 9., Number of unidentate ligand in complex compound is known as .., (A) oxidation number, (B) primary valency, (C) secondary valency, (D) tertairy valency, 10., Which ligand cannot form chelate ?, (A) SO,, -2, (В) Ох2-, (С) 0-, (D) CO,?, 11., Among the given ligand which one has highest number of co-ordation site ?, (A) en, (В) Pn, (С) Ptn, (D) EDTA, 12., Which ligand cannot form complex having cyclic structure ?, (A) Acetate, (В) Охаlate, (C) Ethylene diamine, (D) Propylene triamine, 13., In which of the following complex the primary valency of metal atom is highest ?, (A) K, [Cr,O,], (B) K [MnO,], (C) K, [Fe (CN),], (D) [Mn (en),]Cl;, 14., Which of the following is not a tridentate ligand ?, (A) PO,3, (B) AsO,, (D) вO, 3, -3, (C) N3-, Which ligand is required in least number to satisfy secondary valency of metal atom in complex, compound ?, 15., (A) NH,, (B) en, (С) Ptn, (D) Pn, 16., Which of the following is most stable complex compound ?, (A) [NICI-, (B) [NiF,-, (C) [Ni (H,O),*, (D) [Ni (CN),], 17., Which is the correct order of strength of ligand for stability of complex componds ?, (B) CF< OH¯ < H,0 < NH,, < NH,, (C) OH < H,O < CIF < NH,, (A) CF < H,0 < OH¯ <, (D) OH¯ < CF < H,0 < NH,, 1. (В), 2. (В), 3. (С), 4. (А), 5. (В), 6. (С), 7. (А), 8. (D), 9. (C), 10. (С),, 11. (D), 12. (А), 13. (В), 14. (C), 15. (С), 16. (D), 17. (A), Answers, • Geometrical structure of complex ion :, Geometrical structure of complex depend on magnetic property and hybridisation. In complex if, strong ligand combines with metal ion having co-ordination number 4 then hybridisation is dsp and shape, is square planar. eg. [Ni(CN),). If weak ligand combines with metal ion having co-ordination number 4, then hybridisation is sp and shape is tetrahydral e.g. [NiCl,. In complex if strong ligand combines with, metal ion having co-ordination number 6 then hybridisation is sp'd² and shape is octrahedral. e.g., [Fe(CN),3. In complex ion MnO, and Cro,- hybridisation is d's, there is no unpaired electron in Mn*7, and Cr but they are coloured due to d-d transition by electrons of ligand., 434

Page 5 : Hybridisation and magnetic properties in complex compound, Complex ion, metal, Electron, Hybrid-, Number of, Magnetic, ion, configuration, isation, unpair, property, of metal ion, electron, [V(H,O),J**, [Cr{NH,),j*, [MnF j-, [Mn (CN),-, [Fe(CN),J³-, [FeF-, V3+, d², d'sp, diamagnetic, Cr3+, d3, d'sp, 3, diamagnetic, Mn3+, Sp'd?, 4, diamagnetic, d'sp, d'sp, sp'd?, Mn3+, d4, 2, diamagnetic, Fe3+, 1, diamagnetic, Fe3+, 5, diamagnetic, Fe*2, sp, 4, diamagnetic, [CoF_j-, [Co(NH,),*, [Ni (NH,),*, [NICI,P-, [Ni(CN),1?, Co3+, d6, sp'd?, 4, diamagnetic, d'sp, sp'd, Co3+, paramagnetic, Ni2+, 8P, d8-, 2, diamagnetic, Nit2, sp, diamagnetic, Nit2, d8, dsp?, paramagnetic, [Ni(CO),], Ni, 3d8 4s?, paramagnetic, Cu2+, d°, 1, diamagnetic, IZn(NII,),I*, sp, Zn2+, paramagnetic, 19., Which of the following complex is linear ?, (A) [Ag(NH,),] CI, (B) [Ni(CO),], Which of the following complex possess square planar shape ?, (C) [Fe(CO),], (D) [Cr(CO),], 20., (A) [Ni(NH),Cl,], Which of the following is the hybridisation of metal ion in [Cu(NH,],)²*complex ion ?, (A) sp, In which of the following complex hybridisation of metal is d's ?, (B) K, (Ni(CN),], (C) K,[N¡CI,], (D) K [MnO¸], 21., 2+, (B) d³s, (C) dsp?, (D) sp°d, 22., (A) K[MnO,], (B) K,[NiCl,], (C) K,(NiF,], (D) K,[Ni(CN),], How many unpaired electrons are in valence orbital of complex hexa aqua ferrate (III) ion ?, 23., (A) 1, Which one is not an inner orbital complex ?, (B) 3, (С) 5, (D) 4, 24., (A) [Co(NH,),J**, (B) [Ni(NH,),Cl,], Which complex has highest magnetic moment (only spin) ?, (C) [Fe(CN),J, (D) [FeF,J², 25., (A) [Fe(H,O),**, Which of the following complex is paramagnetic ?, (B) [Co(NH,),*, (C) [Fe(CN),J, (D) [Co(NH,),Cl,], 26., (A) [Ni(NH,), Cl,], (B) K,[N¡CI,], Which complex has magnetic moment (only spin) 2.83 B.M. ?, (C) [Ni(NH,),]Cl,, (D) K,[COCI,], 27., (A) [Ni(CO),], (B) [NİCI,, What is the theoritical magnetic moment of complex [Cr(CO)] ?, (C) [Ni(CN),1, (D) [Ni(NH,),1*, 28., (A) 0, (B) 1.73, (С) 5. 92, (D) 4.90, 435