The current course initially gives a description of structural characteristics of different ionic solids. The thermodynamics of formation of these solids is then presented. Historical markers relative to the design of different scales of ionic radius are mentioned. Models, justification of deviation from the perfect ionic model are described, followed by crystal field theory and its structural and magnetic thermodynamic consequences.

The model of the crystalline solid will gradually be completed with the introduction of the imperfections or faults found in all existing solids. The entire crystal (Perfect + faults) makes up the real solid model. This model of the real crystal is the subject of the second part of this course.

This course is intended to teach students the following:
1 - Know how to describe the main structural types characterising solids
2 - Know how to calculate and interpret the energy of a network solid
3 - Know how to use the ionic radius scale according to Shanon and Prewitt for better understanding of the solid structure
4 - Know how to describe one of the models representing the difference from the perfect ionic model of the solid
5 - Acquire very good knowledge of the consequences of the existence of a crystalline field in a solid
6 - Know how to distinguish between the different types of faults in a solid
7 - Be able to write the mechanism of fault formation in a non-stoichiometric solid
8 - Be able to predict the physicochemical properties in correlation with the formation of faults in the solid

Part A: Crystallised solids, from ionic model to ionocovalent compound
1. Structural characteristics of ionic solids
a) Brief description of compact stacks: cfc, hc
b) MX type ionic solids
b) MX2 type ionic solids
d) Structural relationships between compact MX, MX2 networks and cations with coordination number 4 or 6
2. Structural characteristics of more complex solids
a) Type MO3 compounds
a) Type AMO3 compounds
c) Type AM2O4 spinel type compounds
3. Thermodynamics of the formation of ionic solids
a) Calculating reticular energy. Madelung constant
b) Kapustinskii relation
c) Determining reticular energy from thermochemical cycles
4. Relationship between structure and ionic radius
The ionic radius. The different scales
5. Deviation from the perfect ionic model
a) The Sanderson or partial charge model
b) Mooser-Pearson diagrams
c) Effect of d electrons: Crystalline field theory

Part B: Isolated faults in solids: the real crystal model
I- Stoichiometric compounds
1- Intrinsic faults. Mechanism of fault formation
2- Neutral and charged faults. Elements of effective charges
3- Rules for writing our fault formation reactions
4- Thermodynamics of fault formation and equilibrium

II- Non-stoichiometric aspects of compounds – mechanisms of fault formation
1- Justification of non-stoichiometry
2- Compounds with an anion deficit
3- Compounds with a cation deficit
4- Fault annihilation - shear planes: WO3-x, MoO3-x

III- Solid-state solutions: substitution in solids, doping
1- Substitution by an ion with the same valency: Al2O3-Cr2O3
2- Substitution by an ion with a lower valency
3- Substitution by an ion with a higher valency
4- Order-disorder phenomena: LiFe5O8, Ni2GeO4

IV- Optical properties of solids. Ionic conductors Batteries with solid electrolytes
1- coloured centres
2- ionic conductors
3- Batteries with solid electrolytes

Last Modification : Friday 14 January 2011