Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Chemical Bonding: Covalent Bonds and Resonance Structures

In course

CH-110: Advanced general chemistry I

Le cours comporte deux parties. Les bases de la thermodynamique des équilibres et de la cinétique des réactions sont introduites dans l'une d'elles. Les premières notions de chimie quantique sur les électrons et les liaisons chimiques, exemplifiées en chim ...

Description

This lecture covers the strength of covalent bonds, Kekule and resonance structures, average bond lengths, hypervalent compounds, radicals, formal charges, and oxidation numbers. It also discusses the VSEPR model for molecular shapes.

Instructors (7)

Anne-Clémence Corminboeuf

Beat Fierz

Jacques-Edouard Moser

Jacques-Edouard Moser is titular professor in physical chemistry and is currently directing the Group for Photochemical Dynamics (Moser Group) of EPFL. He is a graduate of the École polytechnique fédérale de Lausanne, where he received a diploma degree (MSc) in chemical engineering in 1982. After two stays in 1984 and 1985 at Concordia University in Montréal (Canada), he earned in 1986 his Ph.D. in physical chemistry at EPFL (Michael Grätzel, thesis advisor). In 1986, he joined the Eastman Kodak Corporate Research Laboratories at Rochester (NY, USA) as a postdoctoral fellow and was later associated with the NSF Center for Photoinduced Electron Transfer at the University of Rochester. Returning to Switzerland, he was appointed as a lecturer of physical chemistry at EPFL in 1992 and was awarded the habilitation and the venia legendi in 1998. He is titular professor since 2005.His research activity focuses on the study of the dynamics of photoinduced electron transfer and charge carrier separation at donor-acceptor heterojunctions and in nanostructured semiconductors. He is the author and co-author of ca 200 scientific papers (H-index 75). He currently teaches general physical chemistry to freshmen students in chemistry. He gives two classes on general- and redox photochemistry in the MSc program in chemistry and chemical engineering and the doctoral programs in energy and photonics. Jacques-E. Moser presided the Swiss Society of Photochemistry and Photophysics (1995-1998) and chaired the jury of the Grammaticakis-Neumann international prize in photochemistry (1999-2001). He was a member of the board of the Swiss Chemical Society (2007-2012). He served as a member of the standing committee of the European Photochemistry Association (1992-2000) and of the executive committee of the division for fundamental research of the Swiss Chemical Society (1999-2014). He was the director of the Section of Chemistry and Chemical Engineering of EPFL and a member of the direction of the School of Basic Sciences from 2007 to 2015.

Jérôme Waser

Jérôme Waser biography and CV's are available on the following website: http://lcso.epfl.ch/waser

Angela Steinauer

Official source

Ontological neighbourhood

Chemistry

Inorganic chemistry: Coordination chemistry

Related concepts (32)

Coordinate covalent bond

In coordination chemistry, a coordinate covalent bond, also known as a dative bond, dipolar bond, or coordinate bond is a kind of two-center, two-electron covalent bond in which the two electrons derive from the same atom. The bonding of metal ions to ligands involves this kind of interaction. This type of interaction is central to Lewis acid–base theory. Coordinate bonds are commonly found in coordination compounds. Coordinate covalent bonding is ubiquitous.

Molecular geometry

Molecular geometry is the three-dimensional arrangement of the atoms that constitute a molecule. It includes the general shape of the molecule as well as bond lengths, bond angles, torsional angles and any other geometrical parameters that determine the position of each atom. Molecular geometry influences several properties of a substance including its reactivity, polarity, phase of matter, color, magnetism and biological activity. The angles between bonds that an atom forms depend only weakly on the rest of molecule, i.

Hypervalent molecule

In chemistry, a hypervalent molecule (the phenomenon is sometimes colloquially known as expanded octet) is a molecule that contains one or more main group elements apparently bearing more than eight electrons in their valence shells. Phosphorus pentachloride (), sulfur hexafluoride (), chlorine trifluoride (), the chlorite () ion, and the triiodide () ion are examples of hypervalent molecules. Hypervalent molecules were first formally defined by Jeremy I. Musher in 1969 as molecules having central atoms of group 15–18 in any valence other than the lowest (i.

Chemical bond

A chemical bond is a lasting attraction between atoms or ions that enables the formation of molecules, crystals, and other structures. The bond may result from the electrostatic force between oppositely charged ions as in ionic bonds, or through the sharing of electrons as in covalent bonds. The strength of chemical bonds varies considerably; there are "strong bonds" or "primary bonds" such as covalent, ionic and metallic bonds, and "weak bonds" or "secondary bonds" such as dipole–dipole interactions, the London dispersion force, and hydrogen bonding.

Formal charge

In chemistry, a formal charge (F.C. or q*), in the covalent view of chemical bonding, is the hypothetical charge assigned to an atom in a molecule, assuming that electrons in all chemical bonds are shared equally between atoms, regardless of relative electronegativity. In simple terms, formal charge is the difference between the number of valence electrons of an atom in a neutral free state and the number assigned to that atom in a Lewis structure.

Related lectures (34)

Chemical Bonding: Lewis Structures and Molecular Shapes

Explores chemical bonding, Lewis structures, molecular shapes, and molecular polarity.

Chemical Bonding: Lewis Structures and Molecular Geometries

Explores chemical bonding through Lewis structures, molecular geometries, and dipole moments.

Advanced General Chemistry I

Covers advanced topics in general chemistry, including the periodic table, electronegativity, exceptions to the octet rule, and chemical bonding.

Atomic Orbitals and Hybridization

Explores atomic orbitals, hybridization, bond formation, and electron delocalization in covalent bonds.

Chemical Bonding: Hybridization and Molecular Shape