coordination chemistry

3.  Complex compounds are a special class of
compounds in which the metal atoms or ions are
bound to a number of anions or neutral
molecules.
 In modern terminology these compounds are
called Coordination compounds.
 Coordination compounds are a type of addition
compounds.

5. Double Salts
 They exist only in solid
state and dissociate into
constituent species in their
solution.
 They loose their identity
in dissolved state.
Coordination Compounds
 They retain their identity in
solid as well as in solution
state.
 They do not loose their identity
in dissolved state.

6. Double Salts
 There properties are
essentially the same as those
of constituent species.
 In double salts the metal
atom/ion exhibits normal
valency.
 Eg:FeSO4(NH4)2SO4.6H2O
Coordination Compounds
 There properties are different
from those of constituent
species.
 The number of negative ions or
molecules surrounding the
central metal atom is beyond its
normal valency.
 Eg:K4[Fe(CN)6]

7.  An aqueous solution of potash alum will give the
tests for K+,Al3+and SO4
2-.
K2SO4.Al2(SO4)3.24H2O→2K++ 2Al3+ + 4SO4
2-
+24H2O
 When potassium ferroyanide is dissolved in water,
it does not give the usual tests for Fe2+and CN1-

8.  The molecule or ions which are coordinated to the
metal atom or ion.
 Eg:K4[Fe(CN)6],the 6 cyanide group coordinated by
Fe2+ and are the ligands.
 Ligands can be negative ions, positive ions or neutral
molecules.
 Ligands are lewis base.
 Central metal atoms are lewis acid

9.  One donor atom or one point of attachment and
can coordinate with the metal ion at only one site
in a complex.
 Eg:Cl
-,NH3, H2O etc.

10.  Two or more donor atom or points of attachments.
 Polydentate ligands are further classified as bi, tri,
tetra etc.

18.  A complex ion has a
metal ion at its centre
with a number of
other molecules or
ions surrounding it.