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Lecture 11 Metals, Metallurgy, and Coordination Chemistry
Text: Chapter 16
Minerals
Most metals are found in nature in the form of solid inorganic compounds called
minerals.
The most important source of metals are oxide, sulfide, and carbonate minerals.
Principal Mineral Sources of Some Common Metals
Meal
Mineral
Composition
Aluminum
Bauxite
Al2O3
Chromium
Chromite
FeCr2O4
Copper
Chalcocite
Cu2S
Chalcopyrite
CuFeS2
Malachite
Cu2CO3(OH)2
Hematite
Fe2O3
Magnetite
Fe3O4
Lead
Galena
PbS
Mercury
Cinnabar
HgS
Titanium
Rutile
TiO2
Ilmenite
FeTiO3
Sphalerite
ZnS
Iron
Zinc
Metals and Metallurgy 1
Metallurgy
Metallurgy is the science and technology of extracting metals from natural sources
and preparing them for practical use.
Five Steps
1. Mining (getting the ore out of the ground)
2. Concentrating (preparing it for further treatment).
 Differences in the chemical and physical properties of the mineral of interest
and the undesired material, called, gangue, are used to separate the components.
 Example: Iron maybe separated from gangue in finely ground magnetite by
using a magnet to attract the iron.
3. Reduction (to obtain the metal in the 0 oxidation state).
4. Refining (to obtain the pure metal).
5. Mixing with other metals (to form an alloy).
 Alloys are metallic materials composed of tow or more elements.
Pyrometallurgy: Using high temperatures to obtain the free metal.
Calcination: the heating of ore to cause decomposition and elimination of a
volatile product.

PbCO 3 s  
 PbO s   CO2 g 
Roasting : A heat treatment to cause chemical reactions between the ore and the
atmosphere of the furnace.
2ZnS s  3O2 g  2ZnO s   2SO2 g 
2MnS 2 s  7O2 g  2MnO3 s  4SO2 g
Metals and Metallurgy 2
Smelting: a melting process that causes materials to separate into two of more
layers.
 Slag consists of mostly molten silicates in addition to aluminates, phosphates,
fluorides, and other inorganic materials.
Refining of iron
Ore, limestone, and coke are added to the top of the furnace.
2Cs  O2 g  2COg
Cs  H 2Og  COg  H2 g
Around 250°, limestone is calcinated to form lime, which reacts with molten silica
to form slag.
CaOl  SiO2 l  CaSiO 3 l
Fe 3O4 s   4COg  3Fes  4CO2 g
Fe 3O4 s   4H2 g  3Fes  4H2 Og 
Hydrometallurgy
It is the extraction of metals from ores using aqueous reactions.
Leaching is the selective dissolution of the desired mineral.
Dilute acids, bases, salts, and sometimes water.
4Aus   8CN – aq  O2 g   2H 2Ol  4AuCN–2 aq  4OH – aq
2Au CN–2 aq  Zn s   Zn CN 2–
4 aq  2Aus
Al 2O3 H 2Os  2H2Ol  2OH – aq  2AlOH–4 aq
Metals and Metallurgy 3
Electrometallurgy
molten salts and aqueous solutions
Molten NaCl using Downs cell.
Cathode : 2Na l   2e –  2Nal
Anode : 2Cl – l   Cl 2 g  2e –
Molten Al2O3 in Hall Process
Bauxite
Al2O3•nH2O
Al2O3 + Na3AlF6 (cryolite)
form lower melting mixture than pure Al2O3
Electrolysis gives aluminum metal
Cathode : Al  l  3e –  All
Anode : Cs  + O2– l   CO2 g   4e –
Rubies!
Al2O3 with small amount of Cr3+ (as Cr2O3)
Blue sapphire
Fe2+, Ti4+
Electrorefining copper
Impure copper anode - dissolves along with impurities
Pure copper collected at cathode
Cu 2 l   2e –  Cus
Ered  0.34 V
2H2 Ol + 2e –  H 2 g  2OH – aq
Ered  0.83 V
Metals and Metallurgy 4
Metallic Bonding
Properties of Metals
 luster
 high heat conductivity
 electrical conductivity
 malleable - sheets
 ductile - wires
Electron-Sea Model
 metal cations in a "sea" of electrons
 electrons are confined to the metal by electrostatic attractions to the cations
 electrons are mobile; they are not confined to any particular metal ion (electrons
are delocalized)
 metal atoms form bonds to many neighbors
Molecular-Orbital Model
 Overlap of atomic orbitals on metal atoms to form molecular orbitals.
 There are a very large number of orbitals in metals.
 The number of molecular orbitals involved equals the number of atomic
orbitals.
 The number of bonding orbitals is equal to the number of anti-bonding orbitals.
 As the number of orbitals increases, their energy spacing decreases until they
band together.
Metals and Metallurgy 5

3p band
vacant
3p

E
²E = h 
~0 J to
excite e-

3s
Mg
3s band
occupied

Mg2
Mg3
Mg10
Mg•
antibonding
bonding
Sc
melting
point, °C
1541
Cr
1857
Metals and Metallurgy 6
Ni
1455
Conduction Band
(Antibonding)
Energy
Antibonding
Band gap
Band gap
Bonding
Valence Band
(Bonding)
Metal
Insulator
Element
Energy Gap (kJ/mol)
Copper
0
Diamond
502
Silicon
100
intrinsic
semiconductor
p-doped
semiconductor
p-dopant: Al, Ga
Metals and Metallurgy 7
Semiconductor
n-doped
semiconductor
n-dopant: P, As
Metals and Metallurgy 8
Alloys
Alloys are materials that contain more than one element and have the characteristic
properties of metals.
Solution alloys are homogenous mixtures.
There are two types of solution alloys.
 Substitutional alloys; in which solute atoms take the positions normally
occupies by a solvent atom.
 Interstitial alloys; in which solute atoms occupy interstitial sites in the metal
lattice.
In susbtitutional alloys the atoms must have similar atomic radii and the elements
must have similar bonding characteristics.
In interstitial alloys, one element (usually a nonmetal) must have a significantly
smaller radius than the other (in order to fit into the interstitial site).
These alloys are much harder, stronger, and less ductile than the pure metal
(increased bonding between the nonmetal and metal).
Steel is an example of an interstitial alloy (contains up to 3 percent carbon).
 Mild steel (< 0.2% carbon) used for chains, nails
 Medium steel (0.2-0.6% carbon) -girders, rails
 High carbon steel (0.6-1.5% carbon) cutlery, tools, springs
Metals and Metallurgy 9
In alloy steels V and Cr are added to steel to increase and improve resistance to
stress and corrosion.
Stainless steel contains C, Cr (from ferrochrome, FeCr2), and Ni.
Heterogeneous alloys : Components not dispersed uniformly
Pearlite, two distinct phases: pure iron and Fe3C, cementite
Intermetallic Compounds - homogenous alloys that have definite properties and
compositions.
CuAl2
duraluminum
Ni3Al
used in aircraft engines
Cr3Pt
used to coat razor blades
Transition Elements
d-block
ns2(n-1)d
transition elements (metals)
• high melting solids (excepts mercury, Hg)
• metallic sheen
• good conductors of electricity and heat
electron configuration
[noble gas core] nsa (n-1)db
Metals and Metallurgy 10
during oxidation s electrons are lost first
(first in, first out)
Oxidation Numbers
1st series
2+, 3+ common
Sc
3+
Ti
4+ (3+)
V
4+, 5+
Cr
3+, 6+
Mn
2+, 4+, 7+
Fe ([Ar]3d64s2)
Fe2+ ([Ar]3d6)
Fe3+ ([Ar]3d5)
Higher oxidation states are more common in the 2nd and 3rd series
ex: RuO4, OsO4 (+8)
Magnetism
If a species contains unpaired electrons it is paramagnetic
If it has no unpaired electrons it is diamagnetic
Ferromagnetism - the magnetic moments become permanently aligned. (Fe, Co,
Ni)
Chemistry of Selected Transition Metals
Chromium
In aqueous solution, Cr reacts with acid to form blue Cr2+;

Crs   2H aq  Cr
2
aq  H 2 g
In air, Cr2+ readily oxidizes to Cr3+:
Metals and Metallurgy 11
4Cr
2
aq  O2 g  4H  4Cr 3 aq  2H2 Ol
In aqueous solution, chromium is usually present in the +6 oxidation state.
In base, chromate (CrO42–) is most stable.
In acid, dichromate (Cr2O72–) is the most stable ion.
Iron
In aqueous solutions iron is present as the +2 (ferrous) or +3 (ferric) oxidation
states.
Iron reacts with non-oxidizing acids to form Fe2+(aq)
In the presence of air, Fe2+ is oxidized to Fe3+.
In acid solution, Fe(H2O)63+ forms, but in base Fe(OH)3 precipitates.
Copper
In aqueous solution, there are to common oxidation states +1(cuprous) and
+2(cupric).
Cu+ has a 3d10 electronic configuration and it’s salts tend to be white and insoluble
in water.
Cu(I) disproportionates easily in aqueous solution.

2Cu aq  Cu
2
aq   Cus
Cu(II) is the more common oxidation state.
Many Cu(II) salts are soluble: CuSO4, Cu(NO3)2, and CuCl2.
Metals and Metallurgy 12
Coordination Chemistry
Coordination Compounds
coordination sphere (all atoms within the brackets)
central metal
ligands
acts as Lewis acid
have at least one lone pair of electrons (Lewis base)
Coordination number number of ligands attached to metal
[Ag(NH3)2]+
central metal:
Ag
ligands:
NH3
coordination number:
2
Ligands
monodentate
"one toothed" donates one pair of electrons
ex:
H2O
NH3
H
H
Br-
CN–
H
O
N
H
Cl-
H
Cl
Br
Metals and Metallurgy 13
C N
Polydentate or chelating ligands
bidentate
"two toothed"
donates two pairs of electrons
H2N
en (ethylene diamine)
O
NH2
O
C
O
H2N
NH2
M
O
2–
O
C
C
C
O
O
O
M
oxalato
H3C
C
O
H
C
–
C
CH3
H3C
O
C
H
C
O
O
M
acac
Metals and Metallurgy 14
C
CH3
N
N
N
N
M
phen
N
H2N
NH2
NH2
tren
edta (ethylene diamine tetraacetic acid) up to 6
O
O
O
O
C
N
N
C
O
Cu
NH2 CH2
O
C
O
2
amino acid chelate
Metals and Metallurgy 15
O
C
O O
metal chelate - results from a polydentate ligand attaching to a metal
0
C
HS
HS
C
H2
CH
C
H2
OH
British Anti-Lewisite
Used to treat heavy metal (Tl, As, Hg, Cr) poisoning by forming water soluble
chelate of the metal, that is eliminated through the kidneys
Metals and Metallurgy 16
Naming Coordination Compounds
1.
In naming a coordination compound that is a salt, name the
cation first
and then the anion.
2.
When giving the name of the complex ion or molecule, name
first, in alphabetical order, followed by the name
the ligands
of the metal.
• if the ligand is an anion whose name ends in -ite or -ate, the final e is changed
to o (sulfate sulfato)
• if the ligand is an anion whose name ands in ide, the ending is changed to o
(chloro, bromo, iodo)
• if the ligand is a neutral molecule, its common name is usually used. The
exceptions are water which become aqua, ammonia becomes ammine, and
CO, called carbonyl
• When there is more than one of a particular monodentate ligand with q simple
name, the number of ligands is designated by the appropriate prefix: di, tri,
tetra, penta, hexa. If the ligand is complicated the prefix changes to bis, tris,
tetrakis, pentakis, hexakis, followed by the ligand name in parentheses.
3.
If the complex ion is an anion, the suffix ate is added to the
metal name.
4.
Following the name of the metal, the oxidation number of
the metal is
given in Roman numerals.
Metals and Metallurgy 17
Geometries
Common coordination numbers are 2, 4, and 6
CN = 2
Linear
CN = 4
Tetrahedral, Square Planar (Common for d8)
CN = 6
Octahedral
M
M
M
M
M
M
Metals and Metallurgy 18
Isomers
Structural Isomers - different bonds
Linkage isomers
O
X
X
X
X
N
M
X
X
O
N
O
M
X
O
X
X
nitrito
red
X
nitro
yellow
Coordination sphere isomers
3+
H2O
H2O
Cr
OH2
H2O
3Cl
OH2
H2O
Cl
Cr
OH2
H2O
OH2
OH2
green
violet
Stereoisomers - same bonds, different spatial arrangements.
Geometric Isomers
Cis and Trans isomers
Cl
Cl
Pt
H3N
Cis
NH3
+
Cl
Cl
NH3
Pt
H3N
Trans
Metals and Metallurgy 19
Cl
Cl •2H2O
H2
N
Cl
Cl
H2
N
NH2
NH2
Co
N
H2
Co
N
H2
Cl
H2N
N
H2
Cl
Cis
Trans
Fac and Mer Isomers
Cl
Cl
N
Cr
Cr
Cl
N
N
Cl
Cl
NH3
NH3
Cl
NH3
Cr
Cl
Cr
NH3
H3N
Fac
Cl
Cl
H3 N
Mer
Metals and Metallurgy 20
Optical Isomers
Mirror images but not superimposable
H3 N
Br
Br
M
M
Cl
I
I
H3 N
enantiomers
NH3
Cl
I
Br
Br
M
M
Cl
-
Cl
NH3
I
Must have four different groups attached to central atom
O
O
O
O
M
HN
M
N
NH
O
O
NH
N
HN
Metals and Metallurgy 21
Bonding in Coordination Compounds
z
x
y
dz2
x
dxy
y
x
z
y
dx2-y2
dxz
z
dyz
Oh
Td
Metals and Metallurgy 22
square planar
x2-y2
xy
z2
xz, yz
Magnetic Properties
High-spin
Low-spin
low splitting orbitals are similar in energy
large splitting
orbitals are dissimilar in energy
Low spin only d4 through d7
²
²
Metals and Metallurgy 23
Oh
Color
Visible spectrum 400 to 700 nm
ROY G BIV
RED
GREEN
700
BLUE
400 nm
INCREASING ENERGY
Combination of Three Primary Colors RED, GREEN, and BLUE
White light is a product of all colors
Absorption of one color produces a combination of the other two
If we see yellow, a combination of red and green, then blue is absorbed.
In transition metal complexes, absorption of light is a measure of the energy levels
of the metal atom or ion.
Absorption of
energy (²)
²
Metals and Metallurgy 24
Oh
The energy of light absorbed by the complex is related to the crystal field splitting,
∆, caused by the ligands.
Spectrochemical Series
Halides < C2O42- < H2O < NH3 = en < phen < CNsmall field splitting
large orbital splitting
small ∆
large ∆
weak field ligands
strong field ligands
Fe(CN)64-
absorbs violet
Fe(H2O)62+ absorbs red
see lemon yellow
see blue-green
Metals and Metallurgy 25
Complex
Wavelength
Color absorbed
Color of Complex
700
red
green
[Co(C2O4)3]3-
600, 420
yellow, violet
dark green
[Co(H2O)6]3+
600, 400
yellow, violet
blue green
[Co(NH3)6]3+
475, 340
Blue, ultraviolet
yellow-orange
[Co(en)3]3+
470, 340
Blue, ultraviolet
yellow-orange
[Co(CN)6]3-
310
Ultraviolet
pale yellow
absorbed
[CoF6]3-
Metals and Metallurgy 26