Chemistry
CHEM 301 LECTURE
Unit 1 0 . COORDINATION CHEMISTRY
Factors t hat affect solubility:
Common ion: decrease in solubility
Complex ion: increase in solubility
How does complex ion formation increase solubility?
Consider the complex ion formation between silver and ammonia:
+
Ag + 2NH3
A g(NH3 )2
+
Kf = 1 .5 x 10
7
where Kf i s the formation constant (always >1 , formation of the complex is highly favorable)
Complex ion formation increases the solubility of sol ids in water.
Example:
Calculate the solubility of AgCl (1.6 x 10
+
-10
) in 1.0 M NH3 .
AgCl
A g + Cl
-
Ksp = 1.6 x 10
Ag + 2NH3
A g(NH3 )2
+
Kf = 1 .5 x 10
+
+
AgCl + 2NH3
Ag(NH3 )2 + Cl
-
K = 2 .4 x 10
-10
7
-3
then:
Complex Ion
• a c harged species in which a central metal (transition) ion is bonded to molecules or ions called ligands
• type of bond: Lewis acid -base
• examples:
metal: acid; base: ligand
+
32
Ag(NH )
Cu(NH3)2+2
Fe(CN)6-4
Coordination Compounds
• c ontains a complex ion
[Co(NH3)6 ]Cl3
Fe4 [Fe(CN)6]3
[Co(H2 O)6 ][Co(CN)6 ]
Ca[Cu(OH)3 (Br)(NH3 )2 ]
1 of 3
CHEM 301 LECTURE
coordination number
• number of atoms bonded to the central atom donor atom
• a tom in the ligand that is directly bonded to the central atom t ype of ligands
• monodentate
• bidentate
• polydentate
Formula Writing
1 . The formula of a complex should be enclosed in square brackets [ ], charged or not.
2 . The symbol of the metal is written first, followed by anionic ligands, and finally by neutral ligands.
Example: Ca[Cu(OH)3 (Br)(NH3 )2 ]
N omenclature
1 . The cation is named before the anion.
Ca[Cu(OH)3 (Br)(NH3 )2 ] calcium _________________________
2 . Within a complex, the ligands are named first, in alphabetical order, the metal ion last. calcium ___ammine___bromo___hydroxocopper____
3 . The number of ligands of the same kind i n a complex is indicated by Greek prefixes
Unit 1 0 . COORDINATION CHEMISTRY
Factors t hat affect solubility:
Common ion: decrease in solubility
Complex ion: increase in solubility
How does complex ion formation increase solubility?
Consider the complex ion formation between silver and ammonia:
+
Ag + 2NH3
A g(NH3 )2
+
Kf = 1 .5 x 10
7
where Kf i s the formation constant (always >1 , formation of the complex is highly favorable)
Complex ion formation increases the solubility of sol ids in water.
Example:
Calculate the solubility of AgCl (1.6 x 10
+
-10
) in 1.0 M NH3 .
AgCl
A g + Cl
-
Ksp = 1.6 x 10
Ag + 2NH3
A g(NH3 )2
+
Kf = 1 .5 x 10
+
+
AgCl + 2NH3
Ag(NH3 )2 + Cl
-
K = 2 .4 x 10
-10
7
-3
then:
Complex Ion
• a c harged species in which a central metal (transition) ion is bonded to molecules or ions called ligands
• type of bond: Lewis acid -base
• examples:
metal: acid; base: ligand
+
32
Ag(NH )
Cu(NH3)2+2
Fe(CN)6-4
Coordination Compounds
• c ontains a complex ion
[Co(NH3)6 ]Cl3
Fe4 [Fe(CN)6]3
[Co(H2 O)6 ][Co(CN)6 ]
Ca[Cu(OH)3 (Br)(NH3 )2 ]
1 of 3
CHEM 301 LECTURE
coordination number
• number of atoms bonded to the central atom donor atom
• a tom in the ligand that is directly bonded to the central atom t ype of ligands
• monodentate
• bidentate
• polydentate
Formula Writing
1 . The formula of a complex should be enclosed in square brackets [ ], charged or not.
2 . The symbol of the metal is written first, followed by anionic ligands, and finally by neutral ligands.
Example: Ca[Cu(OH)3 (Br)(NH3 )2 ]
N omenclature
1 . The cation is named before the anion.
Ca[Cu(OH)3 (Br)(NH3 )2 ] calcium _________________________
2 . Within a complex, the ligands are named first, in alphabetical order, the metal ion last. calcium ___ammine___bromo___hydroxocopper____
3 . The number of ligands of the same kind i n a complex is indicated by Greek prefixes