it explains the basics of coordination geometry coordination geometry class 12 very brilliant presentation

1. Coordination Compounds

2. Introducing Coordination
Compounds
What you will learn
• Importance of Coordination Compounds
• Classification of Salts
• General Formula of Coordination
Compounds and their Important Terms
• Concepts of Central Metal Atom,
Ligands, Coordination Sphere,
Ionisation Sphere and Coordination
Number

3. To Understand
Coordination Compounds,
Let’s First See What Are
Salts!

4. An ionic compound that contains
a cation (basic radical)
and an anion (acid radical)
Salt

5. Salt
Simple salt Double salt Complex salt
Classification of Salts

6. Simple salt is formed by
the neutralization of an
acid and a base.
Simple Salt
NaOH + HCl NaCl + H2O

7. Double Salt
It dissociates into simple ions
completely when dissolved in water.
It is formed by the combination of
two or more stable compounds in
a stoichiometric ratio.

8. Double Salt
KCl + MgCl2 + 6H2O KCl.MgCl2.6H2O
Carnallite

9. The solution shows the properties
of K+
, Mg2+
, and Cl−
ions.
When dissolved in water
KCl.MgCl2.6H2O
Double Salt

10. Double Salt
K2SO4 + Al2(SO4)3 + 24H2O K2SO4.Al2(SO4)3.24H2O
Potash alum

11. Double Salt
When dissolved in water
K2SO4.Al2(SO4)3 .24H2O
The solution shows the properties
4
of K+
, Al3+
and SO 2−
ions.

12. Double Salt
Fe2SO4 + (NH4)2SO4 + 6H2O Fe2SO4.(NH4)2SO4.6H2O
Mohr’s salt
+ =
Ferrous
sulphate
Ammonium
sulphate
Mohr’s
salt

13. When dissolved in water
FeSO4.(NH4)2SO4.6H2O
Double Salt
2+
The solution shows the properties
of Fe , NH4 , and SO4 ions.
+ 2-

14. On qualitative
analysis, a solution
of double salt gives
the test for each
individual
constituent ions.

15. Point to Remember!
Generally, a double salt
contains same anion
but different cations.

16. Complex Salt
But it does not dissociate
into simple ions.
It is formed by the combination of
two or more stable compounds in
a stoichiometric ratio.

17. Complex Salt
When dissolved in water
K4[Fe(CN)6]
The solution does not show t_
he
properties of Fe2+ and CN

18. Complex Salt
K4[Fe(CN)6]
Exists as a
distinct entity
Complex ions are
shown by square
brackets.

19. K4[Fe(CN)6]
Does not dissociate
2+
into Fe & CN ions
to give identification
test
_
Complex Salt
K
+
Gives the
identification
test of K+
4 _
[Fe(CN)6]

20. Complex Salt
CuSO4 + 4NH3 + H2O [Cu(NH3)4]SO4.H2O
Tetraamminecopper(II)
sulphate monohydrate

21. Complex Salt
When dissolved in water
The solution shows the properties
of SO4
2- but does not show of NH3
[Cu(NH3)4]SO4.H2O

22. Exists as a
distinct entity
Complex Salt
[Cu(NH3)4]SO4.H2O
_
Gives test for SO4
2

23. Complex salts
are generally
coordination
compounds.
Do You Know?

24. Coordination Compounds
The addition compounds that retain
their identity (i.e., does not lose
their identity) in solutions are known
as coordination compounds.

25. When KCN solution is added
to Fe(CN)2 solution.
The species K4[Fe(CN)6] is
formed and when dissolved in
water no longer gives test fo
_r
Fe2+
and CN-.
Coordination Compounds

26. The metal atoms are bound to a
number of anions, cations, or neutral
molecules by sharing of electrons.
Coordination Compounds

27. Let’s See the General
Formula of Coordination
Compounds and their
Important Terms!

28. General
formula
a+ a−
[ M ( L )n ] X
Coordination Compounds

29. M
Generally metals
Known as
central metal
atom/ion
Coordination Compounds
Central atom

30. Central Metal Atom/Ion
Behaves as
Lewis acid
Generally, central metal
atom/ion accept
electrons from ligands.
Note: Ligand will be discuss later in this session.

31. Central Metal Atom/Ion
[C
Co
o(NH3)6]Cl3
Central metal
atom/ion

32. General formula
Coordination Compounds
a+ a−
[ M (L)n ] X

33. The electron-rich species
bound to the central atom/ion
inside the square bracket are
known as ligands.
Ligands
Ligand
In general, donates
the electron to central
metal atom
Behaves as
Lewis base

34. Ligands
[C
Co
o
((
N
NH
H3
3)6]Cl3
Ligand

35. General
formula
a+ a−
[ M ( L )n ] X
Coordifi6tiofi Compoufids
Coordination
sphere

36. Coordifi6tiofi Compoufids
General
formula
a+ a−
[ M ( L )n ] X
Charge on
coordination
entity

37. Charge on Coordination Entity
3
3+
+
[Co(NH3)6] 3Cl−
Charge on
coordination
entity

38. Coordination Compounds
General
formula
a+ a−
[ M ( L )n ] X
Counter ion

39. Counter Ion
3
3 6
6
[C
Co
o(NH ) ]3
3
+
+
3Cll−
Counter ion

40. Can counter ion be a
complex compound?

41. Counter Ion as Complex Compound
When there are two coordination
spheres joined together by
ionisation sphere

42. [Ag(NH3)2][Ag(CN)2]
[Cr(NH3)6][Co(CN)6]
Counter Ion as Complex Compound

43. Coordination Sphere
The central atom/ion and the
ligands attached to it are
enclosed in a square
bracket.
In K4[Fe(CN)6], the
coordination sphere is
[Fe(CN)6] .
4_

44. Ionization Sphere
The molecule or ionic species
present outside the
coordination sphere constitute
the ionization sphere.
In K4[Fe(CN)6], the
ionisation sphere is K+
.

45. Coordination Number
General
formula a+ a−
[ M ( L )n ] X
Coordination
number

46. Coordination Number
The number of ligand's donor
atom to which the metal
is directly bonded.

47. 3
3 6
6
[
[C
Co
o(NH ) ]3
3+
3Cl−
Coordination
number
Coordifi6tiofi Number

48. Coordination Number
Coordination number of Pt = 6
Coordination number of Ni = 4
2+
[Ni(NH3)4]
2
_
[Pt(Cl)6]

49. How to calculate the
oxidation number of central
atom/ion in any complex?

50. The charge that a metal
would carry if all the ligands
are removed along with
the electron pairs that are
shared with the central atom
Oxidation Number of Central Metal Atom

51. x + 4(-1) -3
x -1
=
x = +1
Oxidation Number of Central Metal Atom
Oxidation
no. of Cu
3_
[Cu(CN)4]

52. Effective Atomic Number Rule
The sum of electrons on the
central metal atom or ion and
electrons donated from the
ligand is known as effective
atomic number.

53. Point to Remember!
Generally, EAN is equal to
the atomic number of the
nearest noble gas to the
central metal atom.
Radon (Rn) 86
Krypton (Kr) 36
Xenon (Xe) 54

54. Effective Atomic Number Rule
EAN =
Number of electrons in the
central metal atom or ion +
Number of electrons
donated by ligands

55. Effective Atomic Number Rule
All donations contribute
2 electrons
1
NO is considered to
be a 3-electron donor
BUT
For 𝛑-donor ligands,
2
The number of 𝛑 electrons
involved in donation
from a particular ligand
are to be considered.

56. [Cr(CO)6] Electrons in Cr
atom = Atomic
number of Cr
24
Number of
electrons
donated by 6 CO
2 X 6 = 12
36
Obeys EAN
rule
O.S of Cr = 0
Effective Atomic Number Rule

57. Limitation of EAN Rule
The EAN rule fails in
many cases and works
best for metals in low
oxidation states.

58. Some complexes
can be stabilised
by following
EAN rule.
Note!