Class 12 Chemistry - Chapter Coordination Compounds NCERT Solutions | Explain with two examples each of the fo
Explain with two examples each of the following: coordination entity, ligand, coordination number, coordination polyhedron, homoleptic and heteroleptic.
(i) Coordination entity:
A coordination entity is an electrically charged radical or species carrying a positive or negative charge. In a coordination entity, the central atom or ion is surrounded by a suitable number of neutral molecules or negative ions ( called ligands). For example:
[Ni(NH3)6]2+ , [Fe(CN6)]4+ = cationic complex
[PtCl4]2- , [Ag(CN)2]- = anionic complex
[Ni(CO)4] , [Co(NH3)4 Cl2] = neutral complex
(ii) Ligands The neutral molecules or negatively charged ions that surround the metal atom in a coordination entity or a coordinal complex are known as ligands. For example,
, Cl - , - OH. Ligands are usually polar in nature and possess at least one unshared pair of valence electrons.
(iii) Coordination number: The total number of ligands (either neutral molecules or negative ions) that get attached to the central metal atom in the coordination sphere is called the coordination number of the central metal atom. It is also referred to as its ligancy.
For example:
(a) In the complex, K2[PtCl6], there as six chloride ions attached to Pt in the coordinate sphere. Therefore, the coordination number of Pt is 6.
(b) Similarly, in the complex [Ni(NH3)4]Cl2, the coordination number of the central atom (Ni) is 4.
(iv) Coordination polyhedron: Coordination polyhedrons about the central atom can be defined as the spatial arrangement of the ligands that are directly attached to the central metal ion in the coordination sphere. For example: (a) (b) Tetrahedral
(v) Homoleptic complexes: These are those complexes in which the metal ion is bound to only one kind of a donor group. For eg: [Co(NH3)6]3+ , [PtCl4]2- etc.
(vi) Heteroleptic complexes: Heteroleptic complexes are those complexes where the central metal ion is bound to more than one type of a donor group. For e.g.: [Co(NH3)4 Cl2]+ , [Co(NH3)5 Cl]2+
More Questions From Class 12 Chemistry - Chapter Coordination Compounds
- Q:-
[NiCl4]2- is paramagnetic while [Ni(CO)4] is diamagnetic though both are tetrahedral. Why?
- Q:-
Explain on the basis of valence bond theory that [Ni(CN)4]2- ion with square planar structure is diamagnetic and the [Ni(CN)4]2- ion with tetrahedral geometry is paramagnetic.
- Q:-
Draw figure to show the splitting of d orbitals in an octahedral crystal field.
- Q:-
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
(ii) [Co(NH3)5Cl]Cl2
(iii) CrCl3(py)3
(iv) Cs[FeCl4]
(v) K4[Mn(CN)6]
- Q:-
The oxidation number of cobalt in K[Co(CO)4] is
(i) +1
(ii) +3
(iii) -1
(iv) -3
- Q:-
[Cr(NH3)6]3+ is paramagnetic while [Ni(CN)4]2- is diamagnetic. Explain why?
- Q:-
Discuss the nature of bonding in metal carbonyls.
- Q:-
Discuss the nature of bonding in the following coordination entities on the basis of valence bond theory:
(i) [Fe(CN)6]4-
(ii) [FeF6]3-
(iii) [Co(C2O4)3]3-
(iv) [CoF6]3-
- Q:-
Write the formulas for the following coordination compounds:
(i) Tetraamminediaquacobalt (III) chloride
(ii) Potassium tetracyanonickelate(II)
(iii) Tris(ethane-1,2-diamine) chromium(III) chloride
(iv) Amminebromidochloridonitrito-N-platinate(II)
(v) Dichloridobis(ethane-1,2-diamine)platinum(IV) nitrate
(vi) Iron(III) hexacyanoferrate(II)
- Q:-
Predict the number of unpaired electrons in the square planar [Pt(CN)4]2- ion.
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In the button cells widely used in watches and other devices the following reaction takes place:
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3 Comment(s) on this Question
what is mean by coordination entity and how to find it form a complex
What are ligands?
Nice explanation.
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