Lecture

Crystal Field Theory: Square Planar Complexes

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In course

CH-222: Coordination chemistry

Fundamental knowledge of coordination compounds. ...

Description

This lecture covers the rest of crystal field theory, focusing on the splitting diagrams for square planar complexes and the spectrochemical series. The instructor discusses the preference for square planar complexes over other configurations, the impact of ligands on the size of the complexes, and the influence of oxidation state on the complexes' size. The spectrochemical series is explored, highlighting the variations among transition metals and the effect of ligands on the complexes' size.

Instructor

Wendy Lee Queen

Teaching & PhD PhD Students Pratap Narayan Soni, Pattaraphon Rodlamul, Matthieu Meoli, Olivier Thomas Smith, Sanjay Venkatachalam, Anne Faustine Sido Belin, Christopher William Gardner, Lorenzo Meneghin Past EPFL PhD Students Mehrdad Asgari, Daniel Teav Sun, Ilia Kochetygov, Vikram Vinayak Karve, Anita Justin, Till Marian Schertenleib, Jocelyn Richard Roth, Timo Markus Oskar Felder Courses Chemical engineering practice ChE-309 This course provides the students with practical experience wit

Official source

Ontological neighbourhood

Chemistry

Inorganic chemistry: Coordination chemistry

Related concepts (32)

Crystal field theory

In molecular physics, crystal field theory (CFT) describes the breaking of degeneracies of electron orbital states, usually d or f orbitals, due to a static electric field produced by a surrounding charge distribution (anion neighbors). This theory has been used to describe various spectroscopies of transition metal coordination complexes, in particular optical spectra (colors). CFT successfully accounts for some magnetic properties, colors, hydration enthalpies, and spinel structures of transition metal complexes, but it does not attempt to describe bonding.

Ligand field theory

Ligand field theory (LFT) describes the bonding, orbital arrangement, and other characteristics of coordination complexes. It represents an application of molecular orbital theory to transition metal complexes. A transition metal ion has nine valence atomic orbitals - consisting of five nd, one (n+1)s, and three (n+1)p orbitals. These orbitals are of appropriate energy to form bonding interaction with ligands. The LFT analysis is highly dependent on the geometry of the complex, but most explanations begin by describing octahedral complexes, where six ligands coordinate to the metal.

Transition metal

In chemistry, a transition metal (or transition element) is a chemical element in the d-block of the periodic table (groups 3 to 12), though the elements of group 12 (and less often group 3) are sometimes excluded. The lanthanide and actinide elements (the f-block) are called inner transition metals and are sometimes considered to be transition metals as well. Since they are metals, they are lustrous and have good electrical and thermal conductivity.

Post-transition metal

The metallic elements in the periodic table located between the transition metals to their left and the chemically weak nonmetallic metalloids to their right have received many names in the literature, such as post-transition metals, poor metals, other metals, p-block metals and chemically weak metals. The most common name, post-transition metals, is generally used in this article. Physically, these metals are soft (or brittle), have poor mechanical strength, and usually have melting points lower than those of the transition metals.

Spectrochemical series

A spectrochemical series is a list of ligands ordered by ligand "strength", and a list of metal ions based on oxidation number, group and element. For a metal ion, the ligands modify the difference in energy Δ between the d orbitals, called the ligand-field splitting parameter in ligand field theory, or the crystal-field splitting parameter in crystal field theory. The splitting parameter is reflected in the ion's electronic and magnetic properties such as its spin state, and optical properties such as its color and absorption spectrum.

Related lectures (32)

Ligand Field Theory: Crystal Field Splitting

Delves into ligand field theory, crystal field splitting, and molecular orbitals in transition metal complexes.

Splitting Diagrams: Crystal Field Stabilization Energy

Explains splitting diagrams and Crystal Field Stabilization Energy calculations for transition metal complexes.

Coordination Chemistry: Ligands and Geometries

Covers coordination numbers, common ligands, and preferred geometries in coordination chemistry, emphasizing the spatial distribution between ligands and the role of d⁸ electron configurations.

Pi-Donor and P-Acceptor Ligands

Explores the impact of pi-donor and p-acceptor ligands on ligand field splitting diagrams and metal orbitals in coordination complexes.

Crystal Field Theory: Octahedral and Tetragonal Distortions