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Chapter 7 Inorganic Solid State Chemistry
Destination & Requirment
 Basic concepts:
point defect, chemical equilibrium of defect ,
non-stoichiometric compound, solid phase chemical reactions
 Classification and features of point defect
 Basic types of the crystalline defect
 Characteristics and mechanism of solid phase reaction
Introdution
 Inorganic solid materials are one of three pillars for forerunner and
foundation of current era. (materials, energy and information).
 Inorganic solid chemistry is a interdisciplinary subject involving
physics, chemistry, crystallography and a variety of technology
subjects.
 inorganic solid chemistry :
the science about studying the preparation, composition, structure and
properties of solid material.
Content
 Ⅰ. Cmposition and structure of the inorganic solid
 Ⅱ. Crystal defect
 Ⅲ. Solid-phase reaction chemistry
 Ⅳ. Properties and applications of inorganic solids
Ⅰ. Composition and structure of the inorganic solid
 Composition of inorganic solid material:
The type and content of the element constitute the inorganic solid.
In addition to the main ingredients , including the microscale
additives and impurities that have an important influence on structure
and performance of inorganic solid material.
 Structure of inorganic solid material:
the atoms, molecules at the different levels in the form, state and
space distribution when combining with each other.
I. Composition and structure of the inorganic solid
 1.1 Chemical bonds of inorganic solid material
 1.2 Structure types of inorganic crystals
Ⅰ. Composition and structure of the inorganic solid
 1.1 chemical bonds of inorganic solid material
 Chemical bond type and its basic characteristics
Bond types
ionic
covalent
metallic
hydrogen
VdW’s force
Valence
electrons
Localized to ions
Localized
common
delocalized
tiny change
tiny change
character
no saturability
no directionality
saturability
directionality
no saturability
no directionality
saturability,
directionality
no saturability,
no directionality
Bond energy
(kJmol-1)
100 ~ 300
200 ~ 800
50 ~ 150
17 ~ 25
< 20
Ⅰ. Composition and structure of the inorganic solid
 1.2 Structure types of inorganic crystals
Macroscopically, 3D finitive peroidic structure
symmetry: 32 Point group
classified into 7 Crystal system:
Cubic,
Tetragonal/Hexagonal/Trigonal,
Orthorhombic/Monoclinic,
Triclinic
Microscopically, 3D infinitive peroidic structure
Bravais Lattice: 14 in 3D, 5 in 2D.
Generally,
symmetry: 230 Space group
The atomic force micrograph (AFM) of the carbon atoms in the
surface of high orientation graphite crystals (HOPG)
Ⅰ. Composition and structure of the inorganic solid
The diagram of structure of ion crystal
NaCl (rock salt) structure
Ⅰ. Composition and structure of the inorganic solid
Crystalline structure of the atomic crystal and molecular crystal
Adamas
Anthracene
Ⅰ. Composition and structure of the inorganic solid
Metal crystal structure
Closest packing of equal-radius sphere
Hexagonal close packing(hcp): Be, Mg, Zr.（space occupancy:74.05%）
Face-centered cubic close packing(ccp): Ca, Sr, Pb. （space occupancy:74.05%）
Body-centered cubic close packing(bcc): Li, Na, α-Fe.（space occupancy:68.02%）
Ⅰ. composition and structure of the inorganic solid
Crystal type
Ionic crystals
Covalent crystals
Metal crystals
Molecular
crystals
particles
cation and anion
atom
atom,
cation + free electron
polar or nonpolar
molecule
chemical bond
ionic
covalent
metallic
VdWs'force,
hydrogen bond
structural point
large lattice energy,
stable structure,
high CN.,
medium densitive
low CN.,
low densitive
high CN.,
densitive
CN. uncertainty,
low densitive
Mechanical
properties
high stiffness,
high hardness/brittleness
high stiffness,
brittleness
different stiffness,
high plasticity/ductility
loose, soft
Electrical
performance
insulator,
conductive molten
insulator,
insulating molten
electron conductor
insulator
thermal
performance
high melting point,
poor expansion,
ionic melt
high melting point,
poor expansion,
molecular melt
various melting point,
broad liquid temperature
low melting point,
high expansion
optical
performance
colorless or transparent
related with ions
high refractive index
metallic lustre, opaque
transparent
Example
NaCl ,MgO
Adamas , SiC
Fe, Ag, Cu
dry ice, ice
Ⅰ. Composition and structure of the inorganic solid
Mixed bonding crystal
graphite
Hexagonal boron nitride
Ⅰ. Composition and structure of the inorganic solid
Layered Double Hydroxides(LDHs),hydrotalcite
host
Mixed bonding crystal
guest
host
The dodecyl sulphonate
2.5nm
Methyl orange anion
1.9nm
Nitrate
0.7nm
Benzoiate
1.2nm
Ⅰ. Composition and structure of the inorganic solid
Layered Double hydroxides (LDHs): hydrotalcite
[∑M2＋1-x∑M3＋x(OH)2]x+ (∑An-)x/n• zH2O
covalent
bond
intermolecular
interaction
O 2＋O 3O 2＋O 3 O
M
M
M M
＋
O
O
O
O ＋ O
O
O
H H
hydrogen
bond O
An-



An-
various metal elements in host layer
various guest component in interlayers
various chemical bond types
orderly arrangement
O
H H
O
H H
O
H H

dative bond
O 3O 2＋O 3 O
M
M M
＋
O
O
O ＋ O
M2＋
electrostatic
interaction
supramolecular
structure
Ⅰ. Composition and structure of the inorganic solid
1.2 Structure types of inorganic crystals
 Ideal crystals vs. Real crystals
Ideal crystal: crystallography and X-ray diffraction analysis.
Real crystal: material design and preparation.
 In real crystals, the area of ideal periodic arrangement of atoms
is not infinitive, always partly appear irregularity, incomplete,
which is called "defect".
 Defects directly determines optical, electrical, magnetic,
acoustic, thermal and mechanical properties of the real crystals.
Ⅱ. Crystal defect
 2.1 Crystal defect types
 2.2 Chemical equilibrium of defects
 2.3 Non-stoichiometric compound
 2.4 Effect of defect on the properties of materials
Ⅱ. Crystal defect
2.1 crystal defect types
Intrinsic:
0D. point defect
Schottky/Frenkel,
interstitial/substitutional/antisite.
Extrinsic: impurity(interstitial/substitutional)
0D. electronic defect: VB hole and CB electron
Crystal 1D. linear defect:
defect
dislocation (edge/screw/mixed)
2D. planar defect:
twin boundary/stacking fault/small angle boundary
3D. volume defect: impurity/inclusion/vesica
Ⅱ. crystal defect
 2.1 crystal defect types
 Point defect
The extensions of the defects in each direction of crystals are
tiny, which belong to the defect of atomic scale, so also called
0D. defects.
Point defect
Intrinsic defects:
generate due to the imperfect crystal structure.
Such as the ions (or atoms) of crystal displacement from the lattice site
result in vacancy.
Extrinsic//impurity defects:
due to the impurity atoms involved into the crystal.
Ⅱ. crystal defect
 2.1 crystal defect types
Intrinsic/thermal defect
Schottky defect
Frenkel
defect
Ⅱ. crystal defect
 2.1 crystal defect types
Schottky defects concentration
nS
 S
cS 
 exp(
)
N
2kT
nS: Schottky defects number，
N: lattice site number，
S: vacancy generation energy.
Ⅱ. crystal defect
 2.1 crystal defect types
The concentration of the Schottky defects can be measured by thermal expansion
experiment.
Principle: the vacancy defects of ionic crystals can lead to outward expansion
of the ions around the defects due to the disbalance of electrostatic attraction ; in
the metal, the atom around the vacancy relax inward.
Methods: measure the thermal expansion coefficients of the whole crystal and
the thermal expansion coefficient of crystal lattice parameters, lattice thermal
expansion coefficient of crystal including the thermal expansion of lattice and
the expansion due to Schottky defects, the difference of them reflect the
existence and concentration of Schottky defects .
Ⅱ. crystal defect
 2.1 crystal defect types
Frenkel defect concentrations:
nF
F
cF 
 exp(
)
1/ 2
( N  Ni )
2kT
nF: the number of Frenkel defects，
N: cell number，Ni: interstice number，
F:the energy forming a pair of vacancies and interstitial atoms/ions
In general the formation energy of vacancy defects are smaller than the
interstitial defect. Such as copper, the formation energy of vacancy defects is 1
eV, as for interstitial defects which is 4 eV, therefore for 1300 K, the vacancy
concentration of Cu is 10-4, the interstice defect concentration is 10-15.
Ⅱ. crystal defect
 2.1 crystal defect types
Impurity defect
Interstitial impurity defects
Substitutional impurity defects
Small radius atoms or ions enter into the
The atoms or ions whose electronegativity
interstice of crystal atoms to form clearance and radius are similar to the crystal atoms
impurity defects. Such as steel (Fe:C)
replacing the crystal atoms.
Ⅱ. crystal defect
 2.1 crystal defect types
The experiment method to probe point defect
 atomic tracer method
 Isotropic marker method
 Micro-weight method
Ⅱ. Crystal defect
2.2 Quasi-chemical equilibrium of point defect
Thermodynamic theoretical assumptions of point defect：
 A real crystal can be regarded as a solution system, crystal lattice
is the solvent, point defect is the solute;
 If the concentration of point defect is very low, it can be dealed
similar to dilute solution system;
 Electron, hole and various point defects can be regarded as the
atoms, ions, molecules.
Ⅱ. Crystal defect
2.2 Quasi-chemical equilibrium of defect
 Intrinsic semiconductor generated electrons and holes by heated
or radiation , similar to pure water ionization.
[ H  ][OH  ]  K w
n  p  Kg
 Impurities semiconductor ionize out electrons or holes, similar to
the ionization of weak acid and weak base.
NH 4OH  NH 4  OH 
D  D   e'
HCl  Cl   H 
A  A' h 
Ⅱ. Crystal defect
2.3 Non-stoichiometric compound
Definition:
The ionic crystal, whose components are variable within a certain scope,
was called non-stoichiometric compound, also called as Berthollide.
Whileas, most stoichiometric compound are called as Daltonide.
Such as: Fe1-xO 0.09 < x < 0.19
J. L. Proust(1754-1826), French analytical chemist
Law of Definite Composition or Proportion
C.L.Berthollet(1748-1822), French chemist
Chemical equilibrium and revsersible reaction,
Protocoe of mass action law
Ⅱ. Crystal defect
2.3 Non-stoichiometric compound
Forming reason
In compound crystal, if there is only one kind of point defect,
leading to a component excess or another component shortage, which
destroyed the stoichiometry, and formed the non-stoichiometric
compound.
Defect resulted in non-stoichiometry
Ⅱ. Crystal defect
2.3 Non-stoichiometric compound
Classification:
 Metal excess
 Metal shortage
 Inequality between metal vacancy and ions vacancy
Ⅱ. Crystal defect
2.3 Non-stoichiometric compound
Metal excess
1. Anion shortage: TiO2-x, WO3-x, BaTiO3-x
2. Interstitial cation Zn1 + xO
Ⅱ. Crystal defect
2.3 Non-stoichiometric compound
Metal shortage defects
1. Cation shortage: Ni1-xO
2. Interstitial anions: UO2+x
2.3 Non-stoichiometric compound
Inequality between metal vacancy and ions vacancy
-TiOx, x = 0.60-1.35
n(Vti)  n(VO)
Ⅱ. Crystal defect
2.4 The defects influence on crystal performance
Crystal defect affect the optics, thermology, acoustics, electricity,
magnetism and so on physical properties and chemical activity of
crystals.
 -Al2O3 adding a small amount of Cr2O3: ruby
 ZrO2 adding Cr2O3，heat resistance 4 times higher
Ⅲ Solid-phase reaction chemistry
3.1 Solid-phase reaction introduction
3.2 Solid-solid phase reaction
Ⅲ Solid-phase reaction chemistry
3.1 Solid-phase reaction
 Solid-phase reaction definition
 Solid-phase synthesis definition
 Solid-phase reaction basic type
 Solid-phase reaction basic step
 Solid-phase reaction influence factor
Ⅲ Solid-phase reaction chemistry
3.1 Solid-phase reaction
Solid-phase reaction definition
Solid-phase reaction:
the reaction in which solid state substance participates .
Broadly sense: At least, one of the reactants is solid matter;
Narrow sense: Only solid state reactant participated reaction and
the solid product is obtained.
Ⅲ Solid-phase reaction chemistry
3.1 Solid-phase reaction
Solid-phase synthesis definition
The reaction with one of the products is solid state is called solid-phase
synthesis.
precipitation reaction: BaCl2 + H2SO4  BaSO4 + 2HCl
CVD reaction: SiCl4(g) + 2H2(g)  Si(s) + 4HCl(g)
Ⅲ Solid-phase reaction chemistry
3.1 Solid-phase reaction
Solid-phase reaction basic type
 Single solid reaction
 Solid and gas reaction
 Solid and liquid reaction
 Two or more solid reaction
 Solid material surface reaction
Ⅲ Solid-phase reaction chemistry
3.1 Solid-phase reaction
Solid-phase reaction basic step
Solid-phase reaction process, includes the following basic steps:
 Adsorption and desorption;
 Interface reaction;
 Nucleation reaction;
 Mass transport(diffusion/migration) cross interface or phase .
Ⅲ Solid-phase reaction chemistry
3.1 Solid-phase reaction
Solid-phase reaction influence factor
Intrinsic factors:
structure factor, power factor
External factors:
Temperature, irradiation, current and voltage, mechanical stress,
concentration of the liquid phase, gas pressure, pretreatment, etc
Ⅲ Solid-phase reaction chemistry
3.2 Solid-solid phase reaction
 Solid-solid phase reaction mechanism
 Solid phase diffusion
 Solid phase sintering reaction
Ⅲ Solid-phase reaction chemistry
3.2 Solid-solid phase reaction
Solid-solid phase reaction mechanism
MgO (s) + Al2O3 (s) = MgAl2O4(s)
based on the thermodynamics, reaction can occur
1200℃: no reaction
1500℃: reaction for a few days
Ⅲ Solid-phase reaction chemistry
3.2 Solid-solid phase reaction
Solid-solid phase reaction mechanism
MgAl2O4：
(a) MgO/MgAl2O4 interface：
2Al3+－3Mg2+ + 4MgO = MgAl2O4
(b) MgAl2O4/Al2O3 interface：
3Mg2+－2Al3+ + 4Al2O3 = 3MgAl2O4
overall reaction:
MgO + Al2O3 = MgAl2O4
Ⅲ Solid-phase reaction chemistry
3.2 Solid-solid phase reaction
The diffusioin solid phase
The solid phase diffusion mechanism
Direct exchange
Interstitial mechanism
Rotation exchange
Vacancy mechanism
Ⅳ Properties and application of inorganic solids
Properties of inorganic solids
Research characterization of materials under atmosphere conditions
The macroscopic reflection of microstructural characteristics
Process performance
endure the various processing and
manufacturing process does not
result on new defects or residual
Application performance
the properties work well for the normal
use of products ( or device)
Chemical/mechanical/physical properties
Ⅳ Properties and application of inorganic solids
4.1 Chemical properties and applications of inorganic solids
4.2 Mechanical properties and application of inorganic solids
4.3 Physical properties and applications of inorganic solids
Ⅳ Properties and application of inorganic solids
4.1 Chemical properties and applications of inorganic solids
Chemical properties of materials
The ability of material about resists various kinds of medium, including
corrosion resistance, infiltration resistance, oxidation resistance, etc, belong
to the chemical stability of materials. In addition, the chemical properties
including catalytic and ion exchange properties.
The chemical stability of the material depends on the composition and
structure, and also decided by the material density and porosity which belong
to microstructure, dissolution and oxidation belong to chemistry, wetting effect,
temperature, and freezing thawing belong to physical factors.
Ⅳ Properties and application of inorganic solids
4.1 Chemical properties and applications of inorganic solids
Corrosion resistant materials
This kind of material has good chemical
stability and wear resistance, include
materials based on SiC , ZrO2 and ZrO2
toughening, Al2O3 .
Ⅳ Properties and application of inorganic solids
4.2 Mechanical properties and application of inorganic solids
Mechanics properties of inorganic solid
The deformation and damage resist ability of materials, when
subjected to external forces, usually included strength, plasticity,
toughness and hardness, abrasion resistance and fatigue
characteristics.
Mechanical properties is the main performance for structural material.
For functional materials, mechanical properties were also needed except
physical and chemical properties.
Ⅳ Properties and application of inorganic solids
4.2 Mechanical properties and application of inorganic solids
Main mechanical performance indexes
 Strength： The ability to resist plastic deformation or fracture under external
force.
Plasticity ： produce permanent deformation under the action of external force ,
but without damaging its integrity.
Hardness： used to measure the degree of hardness and softness solid of material
which reflect the ability of resist plastic deformation .
Ⅳ Properties and application of inorganic solids
4.2 Mechanical properties and application of inorganic solids
 Toughness ：The ability of resisting to the crack initiation and extension
 Wear resistance ： The ability of resistance to wear and tear under the condition
of friction.
 Fatigue properties ： Materials were damaged and fractured in circulation load.
Ⅳ Properties and application of inorganic solids
4.2 Mechanical properties and application of inorganic solids
Strengthening and toughening ways of inorganic materials
 Eliminating defects of materials, improving the integrity of the crystal
 Thermal toughening technology
A layer of compressive stress in materials surface caused by artificial prestressing
to improve the material tensile strength.
 Chemical reinforcement
The molar volume of the surface is larger than the internal which is changed
by the surface chemical composition.
Ⅳ Properties and application of inorganic solids
4.2 Mechanical properties and application of inorganic solids
Phase transformation toughening
In order to achieve the effect of toughening, phase transformation of
polycrystalline multiphase ceramics in different temperature was applied.
 Out-phase dispersion strengthening and toughening
When the second phase particles introduced in matrix, crack will be segergated
and branched which will change the stress concentration of the crack tip leading to
the improved toughness.
Fiber or whisker reinforcing toughening
Ⅳ Properties and application of inorganic solids
4.2 Mechanical properties and application of inorganic solids
Materials with high strength and tenacity
Commonly used for structural components such as: engine cylinder cover, sealing
ring in chemical machinery, mechanical cutting tools, etc.
Ⅳ Properties and application of inorganic solids
4.2 Mechanical properties and application of inorganic solids
Parts of ceramic engine
Ⅳ Properties and application of inorganic solids
4.3 Physical properties and applications of inorganic solids
Physical properties
Thermal
Heat capacity, thermal conductivity, thermal expansion,
thermal radiation, thermoelectric potential, thermal stability,
melting and sublimation, etc.
Electrical
Electrical conductivity, dielectric, piezoelectric effect,
pyroelectric effect and ferroelectric effect, temperature
coefficient, dielectric loss, etc
Optical
Optical radiation and its interaction with the material,
structural defects and color, light and laser
Magnetic
Diamagnetic, paramagnetic, ferromagnetic, permeability,
ferromagnetic and antiferromagnetic, magnetic domain and
magnetic hysteresis loop, magnetic energy product, etc