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Complex Ions
Complex Ion•An ion formed when a positive central element binds with multiple ions
or polar molecules
Complex Ion•The central
element is almost always a positively
charged metal
Describe or define a
Complex Ion
Anion•Negatively charged ion
Cation
•Positively charged ion
Metal Ion Examples Cu+2 Cu+ Au+
Ag+ Zn+2 Ni+2
Pt+2 Co+2 Al+3
Ligands•The negative ions or polar molecules bound by the central element
in a complex ion
Ligand Examples
•Cl- F- H2O
•NH3 CN- Br-
•NO O2 OH-
Polydentate Ligands
• Ligands that can bind to more than
one point
Bidentate Ligands
•Ligands that can bind to two points in a complex ion
Bidentate Examples
H2N-CH2-CH2-NH2
-O2C-CO2-
Tridentate Ligands
•Ligands that can bind to three points
in a complex ion
Tridentate Examples
H2-C-COO-
HO-C-COO-
H2-C-COO-
Chelates•Polydentate ligands
that bind to metal ions in solution
Coordination Number
•The number of points in which ligands bind to the central element
in a complex ion
Coordinate Covalent Bond•Covalent bonds in which both electrons involved are donated
by one atom
Complex Ions•The bonds formed in a
complex ion are coordinate covalent
bonds
Coordination Complex
•A complex ion and its counter ion
Complex Ions•The bonds formed in a
complex ion are coordinate covalent
bonds
Complex Ion•Because of the type
bonding, they are sometimes called
coordinate complexes
1) Name cations before anions
Naming Complexes
2) Name ligands before metal in the
complex ion
2) Naming Ligands
a) give neutral compds normal names except:
H2O aqua
NH3 amine
CO carbonyl
NO nitrosyl
2) Naming Ligands
b) change -ide endings to -o for
all anions
2) Naming Ligands d) use geometric
prefixes for monodentate
ligands
2) Naming Ligands e) use bis- for 2 &
tris- for 3 polydentate ligands
3) Naming Metal a) use the normal
name if the complex ion is (+)
3) Naming Metal b) make the metal
ending -ate if the complex ion is (-)
3) Naming Metal d) use Roman numerals in () to
indicate metal ox #
Name the Following:
[Pt(NH3)4]Cl2
[Co(H2O)2Cl4]-2
[Cu(H2O)2(en)2]I2
Predict # of isomers of each:
[Pt(NH3)4 Cl2]
[Co(H2O)3Cl3]
Complex Ion Shapes
2-linear 4-tetrahedral or sq pl
6-octahedral
Geometric Isomers
Square planar vs tetrahedral
cis vs trans
Geometric Isomers
Bunched octa-
T-shaped octa-
bis: cis vs trans
Optical Isomers Tri-bis mirror
images
Field Strength
CN- > NO2- > en >
NH3 > NCS- > H2O > F- > Cl-
Field Strength CN- is strong field
Cl- is weak field
Field Strength Determines d-level
splitting or o(splitting energy)
Field Strength Largeo yields low spin or diamagnetic
compds
Field Strength Smallo yields high spin or paramagnetic
compds
[Pt(NH3)2I4]-2
Determine:
Name, shape, & possible isomerism
[Co(NH3)6]+3 yellow[Co(NH3)5NCS]+2 orange[Co(NH3)5H2O]+2 red[Co(NH3)5Cl]+2 purplet-[Co(NH3)4Cl2]+1 green
Complex Ion Equilibria
Cu+2 + 4 NH3 [Cu(NH3)4]+2
[Cu(NH3)4]+2
[Cu+2][NH3]4Kf =
Calculate the ratio of [Cu+2]/ [Cu(NH3)4]+2 when Cu+2 is added to a 0.10 M
NH3 solution:Kf = 2.0 x 1012
Common Ion Equilibria
•The larger the Kf, the more likely the complex will form
Common Ion Equilibria
•Kf for [Ag(NH3)2]+1
= 1.7 x 107
•Kf for [Ag(CN)2]-1
= 2.0 x 1020
Common Ion Equilibria
•Kf for [M(NH3)2]+2
= 1.7 x 107
•Kf for [M(CN)4]-2
= 2.0 x 1020
Common Ion Equilibria
CN- will replaceNH3 in the
complex with silver
Calculate: a) coordination #
b) number of isomersc) oxidation # of metal
[Zn(NH3)2H2OF]+1
[Co(NH3)3ClFI]-1