- What are coordination compounds?
- Types
- Terminologies
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LIGANDS |
CENTRAL
METAL ION/ ATOM |
|
😊Species having at least one lone pair of
electron and donate its lone pair of electron to the central metal cation. 😊Electron rich site and hence called as Lewis
base/ nucleophile. |
😊They do accept that lone pair of electron. 😊Electron deficit site and hence called as Lewis acid/ electrophile. |
So when a group of ligands donate its lone pair of electron i.e., one donor atom of a ligand donates one pair of electron to the metal cation/ atom, coordinate bonds are formed and the result is called complex ion.
A compound with that complex ion is called as coordination compound.
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NEUTRAL COMPLEX COMPOUNDS |
IONIC COMPLEX COMPOUNDS |
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[Pt(NH3)2Cl2] [Co(NH3)3Cl3] |
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[Pt(NH3)2Cl2]👉❌DISSOCIATE
Diamminedichloroplatinum(II)
[Co(NH3)3Cl3]👉❌DISSOCIATE
Triamminetrichlorocobalt(III)
*NOTE: The above complexes in aqueous medium does not dissociate into its constituent ions.
[Co(NH3)6]Cl3 👉 [Co(NH3)6]3+ + 3Cl-
Hexamminecobalt(III) chloride
K4[Fe(CN)6]👉4K+ + [Fe(CN)6]4-
Potassium hexacyanoferrate(II)
[Pt(NH3)4][PtCl4]👉[Pt(NH3)4]2+ + [PtCl4]2-
Tetrammineplatinium(II) tetrachloroplatinate(II)
*NOTE: The above complexes in aqueous medium undergoes partial dissociation.
Unlike double salts coordination compounds do not loose their identity and do not give positive test for all their constituent ions!
IONISATION SPHERE ←K4[Fe(CN)6]→COORDINATION SPHERE
↙ ↘
CENTRAL METAL ION LIGANDS
- The central metal ion bonded to the ligand via coordinate covalent bond is always written within the square bracket is called as coordination sphere.
- The cation/ anion outside the coordination sphere is called as ionization sphere or counter ion.
- The atom in the ligand which is directly attached to the central metal ion is called as donor atom.
- The number of donor atoms attached to the CMI is called as coordination number.
