Unit SOLID STATE CHEMISTRY

Course
Chemistry
Study-unit Code
A000755
Curriculum
In all curricula
Teacher
Riccardo Vivani
Teachers
  • Riccardo Vivani
Hours
  • 42 ore - Riccardo Vivani
CFU
6
Course Regulation
Coorte 2019
Offered
2021/22
Learning activities
Affine/integrativa
Area
Attività formative affini o integrative
Academic discipline
CHIM/03
Type of study-unit
Opzionale (Optional)
Type of learning activities
Attività formativa monodisciplinare
Language of instruction
English
Contents
Main types of crystal structures. Ionic solids: lattice enthalpy, point defects, basic elements of defect thermodynamics, ionic transport and defects. Solid electrolytes and their applications. Electronic structure of solids: the free electron model, band structure of metals and semiconductors.
Reference texts
"Solid State Chemistry and its applications", A.R. West, Ed. Wiley.

"Solid State Chemistry, an Introduction", L.E. Smart, E.A. Moore, Ed. CRC Press.
Educational objectives
Main acquired knowledge

- Notion of unit cell, asymmetrical unit, crystal lattice, cristalline systems.
- Knowledge of the main crystalline structures.
- Factors determining the structure and the stability of ionic solids.
- Knowledge of the main defect types.
- Chemical potential of point defects.
- Dependence of ionic transport on defect types / structural features.
- Application of solid electrolytes in the electrochemical conversion of energy.
- Bond nature, specific heat and electrical conductivity of metals.
- Fermi energy in metals.
- Typologies and properties of semiconductors.

Main skills
- To determine the Miller indexes of lattice planes and calculate the interplanar distance on the basis of the unit cell parameters.
- To calculate the coordination numbers of cations and anions of an ionic crystal through the local electroneutrality condition.
- To calculate ionic radii through the electron density maps.
- To write the reactions for defect formation, the electroneutrality condition for charged defects and to calculate the defect concentrations.
- To predict qualitatively the charge transport properties of an ionic solid on the basis of its structure.
- To calculate the activation energy for ionic conduction, the enthalpy of defect formation and the migration enthalpy of the charge carrier.
- To calculate the Fermi Energy on the basis of the electronic configuration and of the unit cell parameters of a metal.
- To calculate the number of occupied electron states for a metal in a given energy range on the basis of the Fermi gas model.
- To calculate the concentration of charge carriers for an extrinsic semiconductor on the basis of the concentration of the heterovalent impurities.
Prerequisites
You must have passed the General and Inorganic Chemistry course and followed the Inorganic Chemistry and the Physical Chemistry courses. Elemental knowledge of differential and integral calculus is necessary.
Teaching methods
The Solid State Chemistry course consists in 21 lectures, 2 hours each, on all subjects of the course. Duplicated lecture notes edited by the teacher are available.
Other information
Lecture room: library of the Materials Chemistry Laboratory, Department of Chemistry, Biology and Biotechnology (buiding B).
Learning verification modality
The exam of the Solid State Chemistry course consists in an oral interview of about half an hour on topics treated during the course (elements of crystallography, structure and transport electric properties of ionic solids, electronic structure and conductivity of metals and semiconductors). The first topic of the interview is chosen by the student. The test aims at ascertaining the knowledge level of the program topics and at testing the student communication skills and the his ability to process the acquired knowledge.
Extended program
Definition of crystal and basic elements of crystallography. Hexagonal and cubic close-packed structures. Size of atoms and ions; Pauling rules to predict the structure of ionic solids. Determination of lattice enthalpy from thermodynamic data and from the model of ideal ionic solid.

Definition and classification of defects. Basic elements of defect thermodynamics: chemical potential of defects. Frenkel and Shottky defects. Colour centres in the alkaline halides.

Conductivity of ionic solids according to the "random walk" theory. Ionic conductivity of NaCl and AgCl.

Solid electrolytes: general properties and applications. Examples of solid electrolytes based on Ag+ e Na+. Proton conducting solid electrolytes and mechanisms of proton transport. Proton conductors made of perovskite type oxides and of aromatic and aliphatic perfluorinated polymers. Application of proton conductors in fuel cells.

Physicochemical and structural properties of metals. The free electron gas theory: the Drude-Lorentz and the Fermi gas models. Electrical conductivity and heat capacity of metals according to the Fermi gas model. Electron-lattice interaction and band structure. Qualitative description of the band structure for Na, Mg, Al and C(diamond).

Band structure and electrical transport properties of semiconductors. Intrinsic and extrinsic semiconductors; p and n type semiconductors. Electrical conductivity versus temperature for intrinsic and extrinsic semiconductors. The p-n junction: properties and applications.
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