Acids Bases

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Acids Bases
Arrhenius
proton donor hydroxide donor H OH-
Bronsted
proton donor proton acceptor
Lewis
electron pair () electron pair ()
acceptor donor
2
Coordinate covalent bond (dative bond) one
molecule provides both electrons (Lewis base)
the other molecule accepts electron pair into
an empty orbital (Lewis acid)
3
Periodic Table ion formation
H
He
Li Mg
B C N O
F Ne
Na Mg
Al Si P S
Cl Ar
Transition metals - variable
K Ca Sc Ti V Cr Mn Fe Co Ni Cu
Zn Ga Ge As Se Br Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag
Cd In Sn Sb Te I Xe
Cs Ba La Hf Ta W Re Os Ir Pt Au
Hg Tl Pb Bi Po At Rn
Fr Ra Ac Rf Db Sg Bh Hs Mt Ds
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm
Yb Lu
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md
No Lr
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Transition Metals Oxidation states
Table 25-1 on page 908
d1s2
d2s2
d3s2
d5s1
d5s2
d6s2
d7s2
d8s2
d10s1
d10s0
Sc Ti V Cr Mn Fe Co Ni Cu Zn 3 d0 3 d1
3 d2 0 d6 1 d6 0 d8
0 d9 0 d10 1 d10 2 d10
4 d0 5 d0 2 d4 2 d5 2
d6 1 d8 2 d8 2 d9
3 d3 3 d4
3 d5 2 d7
4 d2 5 d2
3 d6
6 d0 7 d0
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Transition Metals Coordination compounds
Transition metals often have empty d orbitals
The orbitals can act a Lewis acids
They form coordinate covalent bonds with other
molecules (ligands) which act as Lewis bases by
donating a lone pair of electrons.
Coordination compounds may have gt octet and their
geometry can be tetrahedral, trigonal
bipyramidal, octahedral, etc.
Coordination compounds often absorb light in
visible range and thus have various colors
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Coordination compounds - example
Hexaaquachromium (III) complex ion
Cr(OH2)63
As neutral compound Cr(OH2)6(NO3)3
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Coordination compounds Ligands
(Table 25-4) on page 911 monodentate
(takes up one orbital place)
..
OH2 aqua
NH3 ammine
CO carbonyl
CN- cyano
PH3 phosphine
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Polydentate Ligands - Table 25-5 on page 912
ethylenediamine (en) bidentate
.. .. H2N-CH2-CH2-NH2
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Nomenclature page 913
1) Cation name 1st (leave a space) anion name

• a) Ligands named in alphabetical order
• b) ligand prefixes
• mondentate di, tri, tetra, penta,
  hexa (not in alphabet)
• (polydentate) bis (2), tris (3),
  tetrakis (4) (not in alphabet)

3) Anionic ligands end in o (chloro, nitro,
hydroxo, etc.)
4) Neutral ligands names either unchanged or
(table 25-4 p911)
5) Roman Numerals designate metal oxidation
states (II).
6) -ate ending used for metals in complex
anions (Table 25-6 p913)
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Cu(NH3)2(H2O)22
K3FeF6
(NH4)2Fe(H2O)F5
K4Mo(CN)8
Fe(CO)5
CrF63-
Rh(CN)2(en)2
Cr(NH3)4SO4Cl
Potassium hexacyanomanganate(III)
sodium tetracyanozincate(II)
tetraamminedichlorocobalt(III) nitrate
hexaamminechromium(III) tetrachlorocuprate(II)
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Coordination compounds geometry
Table 25-7 on page 914
Coordination geometry
example(s)
2 linear Cu(CN)2-
4 tetrahedral Zn(CN)42-
square
planar Ni(CN)42-
5 trigonal bipyramidal Fe(CO)5
square
pyramidal Ni(CN)53-
6 octahedral Fe(CN)64-
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Isomers same formula but different compounds.
NH3
NH3
Cl
Cl
Pt
Pt
Cl
NH3
Cl
NH3
cis pale yellow
trans dark yellow
diamminedichloroplatinum (II) square
planar
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Transition Metals Oxidation states
Table 25-1 on page 908
d1s2
d2s2
d3s2
d5s1
d5s2
d6s2
d7s2
d8s2
d10s1
d10s0
Sc Ti V Cr Mn Fe Co Ni Cu Zn 3 d0 3 d1
3 d2 0 d6 1 d6 0 d8
0 d9 0 d10 1 d10 2 d10
4 d0 5 d0 2 d4 2 d5 2
d6 1 d8 2 d8 2 d9
3 d3 3 d4
3 d5 2 d7
4 d2 5 d2
3 d6
6 d0 7 d0
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z
y
x
dxy, dxz, dyz electron density between axes
dz2 and dx2-y2 electron density located along x
y axes
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eg dz2 dx2-y2
t2g dxy, dxz, dyz
z
z
y
y
x
x
dxy, dxz, dyz electron density between axes
dz2 and dx2-y2 along x y axes
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Crystal Field Theory A ligand is a Lewis
base electron pair donor
In transition metal atoms all 5 d orbitals have
the same energy They are called degenerate.
The ligands may approach central metal ion/atom
along axes, e.g octahedral, or between axes,
e.g. tetrahedral.
These ligands will be repelled by the electrons
occupying orbitals along the direction in which
they approach. This is the concept of the crystal
(electric) field.
The repulsion caused by Ligand fields overlapping
the Metal ion/atom field will raise the energy
of the eg orbitals (octahedral) or the energy of
the t2g orbitals (tetrahedral).
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Splitting energy Doct Pairing energy P
CoF63- vs. Co(CN)63-
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high energy low
energy
E hn J Js ? s-1 h 6.626 x
10-34 Js
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Spectrochemical Series
Ligands influence the value of Doct by virtue of
their crystal field strength. Strong field
ligands produce larger splitting energy (Doct).
I- lt Br- lt Cl- lt F- lt OH- lt H2O lt (COO)22- lt NH3
lt en lt NO2- lt CN-
High spin complexes gtgtgtgtgtgtgtgtgtgtgtgtgtgtgtgtgtgtgtgtgtgtgt Low
spin
e.g. Ni2 d8 octahedral complexes with . H2O,
bipyridine, en, NH3, glycine
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Light
Violet blue green yellow
orange red
Color
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Ni(H2O)62
Ni(bipyr)32
Ni(en)32
Ni(gly)3
Ni(NH3)62
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Weak field ligand
l
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Periodic Table ion formation
H
He
Li Mg
B C N O
F Ne
Na Mg
Al Si P S
Cl Ar
Transition metals - variable
K Ca Sc Ti V Cr Mn Fe Co Ni Cu
Zn Ga Ge As Se Br Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag
Cd In Sn Sb Te I Xe
Cs Ba La Hf Ta W Re Os Ir Pt Au
Hg Tl Pb Bi Po At Rn
Fr Ra Ac Rf Db Sg Bh Hs Mt Ds
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm
Yb Lu
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md
No Lr
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