202 Symmetry and Bonding


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202 Symmetry and Bonding

Course information:

All the information you need for this course will be accessible from this site.

use the sidebar to access a specific lecture, workshop and other materials.

Tutorials and homework form part of this course and are examinable. Extra reading and on-line material is associated with each lecture, this is entirely optional! If you want to find out still more please contact me, I can recommend a wider variety of texts, including those which cover material in more detail.

Need some help!

Check the recommended text for this course:

Group Theory for Chemists, Kieran C. Molloy, Harwood Publishing, Chichester, 2004.

Check the questions answered list!

I will add questions that people ask me (along with my answers!) here: Questions answered.

Ask your class mates and friends

This is good for you and them, teaching and explaining something really helps you understand it yourself. You could also get together with your friends and try to talk material through, discussing material is actually a good way to learn.

Contact Me

I'm very happy to revceive questions via e-mail:

Test preparation(updated for 2023)

  • general test preparation guide
    • test preparation is best started with a hand-written summary of key concepts from each lecture
    • this process ensures you understand each sub-topic and the process of synthesising or condensing the information down helps to embed it in your knowledge framework
    • then engage in active learning of the material, this means being able to recall and write down the summary concepts without using any of your notes
    • then working on some practice questions, to become familiar with processes, it is important to do these without looking at the answers first
    • I strongly discourage revision that consists of only working through old questions
  • 2022 test and model answer pdf
  • revise your assignment and view the model answer
  • I have provided 37 questions with detailed model answers as part of in-lecture activities and end of lecture self-study problems
  • the recommended text also has questions and provides (some) model answers

Lecture 1

(updated for 2023)
  1. notes for the lecture: pdf
  2. slides from the lecture pdf (15 MB file)
  3. flow chart pdf
  4. model answers to the in-class problems/self-study problems/test preparation: pdf
  5. added after feedback practice problems for point group flow chart: pdf
  6. resources related to this lecture optional
    • Reading: Part 1: Ch1 Symmetry from Group Theory for Chemists
    • Chemtube3d is a good website for viewing symmetry elements on 3d rotateable molecules: Chemtube3d
    • Otterbein Gallery has some good examples, and the molecules can be rotated/moved: Otterbein Gallery
    • wiki on symmetry in general

Lecture 2

(updated for 2023)
  1. notes for the lecture: pdf
  2. character tables for the lecture: pdf
  3. slides from the lecture pdf (8 MB file)
  4. model answers to the in-class problems/self-study problems/test preparation: pdf
  5. required Degenerate representations pdf
  6. resources related to this lecture optional
    • Reading: Part 1: Ch2 Groups and Representation from Group Theory for Chemists
    • Greek letters
    • Improper rotations for the Oh point group pdf
    • Where the symbols for the irreducible representations come from pdf
    • Find out more about H3+ h3plus.uiuc.edu

Lecture 3

(updated for 2023)
  1. notes for the lecture: pdf
  2. slides from the lecture pdf (8 MB file)
  3. model answers to the in-class problems/self-study problems/test preparation: pdf
  4. required Infinite rotation groups pdf
  5. resources related to this lecture optional
    • Reading: Part 3: Ch6 Fundamentals of MO Theory from Group Theory for Chemists
    • Reading: Chapter 1.13: Homonuclear diatomic MO theory from Inorganic Chemistry Catherine Housecroft and Alan Sharpe, 2nd Edition, Pearson, Prentice Hall, Harlow, 2005
    • Reading: Chapter 2: MO theory from Shriver and Atkins Inorganic Chemistry Atkins, Overson, Rourke, Weller, Armstrong , 4th Edition, Oxford University Press, Oxford, 2006
    • "The Orbitron"
    • recent Chemistry World (magazine of the Royal Chemical Society) article Bond order through a molecular orbital lens
    • recent Chemistry and Engineering News (magazine of the American Chemical Society) article Boron makes quadruple bond with rhodium
    • famous theoreticians:

Lecture 4

(updated for 2023)
  1. notes for the lecture: pdf
  2. slides from the lecture pdf
  3. model answers to the in-class problems/self-study problems/test preparation: pdf
  4. resources related to this lecture optional

Lecture 5

(updated for 2023)
  1. notes for the lecture: pdf
  2. slides from the lecture pdf
  3. model answers to the in-class problems/self-study problems/test preparation: pdf
  4. resources related to this lecture optional
    • Reading: Part 3: Ch7 H2O Linear or Angular? from Group Theory for Chemists

Lecture 6

(updated for 2023)
  1. notes for the lecture: pdf
  2. slides from the lecture pdf
  3. model answers to the in-class problems/self-study problems/test preparation: pdf
  4. required Mini "tutorial" on B2H6 MO diagram pdf
  5. resources related to this lecture optional
    • Reading: Part 3: Ch7 H2O Linear or Angular? from Group Theory for Chemists
    • Related reading to do after L8: Part 3: Ch8 NH3 Planar or Pyramidal? from Group Theory for Chemists
  6. resources related to forming complex MO diagrams optional
    • there are a number of ways of generating the MOs for B2H6. I have shown you one way which is covered in p 124-127 of Inorganic Chemistry, Catherine Housecroft and Alan Sharpe, 2nd Edition, Pearson, Prentice Hall, Harlow, 2005
    • Another way of treating the MOs of diborane is to assume sp2 hyrbids on the B atoms, this is covered in p89-90 of the course text: Group Theory for Chemists. This section offers some additional insight but you do not need to know how to use hybrid orbitals in this way!
    • Have a look at these papers: for experts
      "Qualitative molecular orbital study of ethane and diborane" by B.M. Gimarc, J. Am. Chem. Soc, 1973, 95(5), p1417-1421 DOI: 10.1021/ja00786a010.
      "Strengths of A-A Single Bonds io Symmetric A2Bzn Molecules and Ions" by B. Gimarc, S. Khan and M.Kohn, J. Am. Chem. Soc, 1978, 100(7), p1996-2003 DOI: 10.1021/ja00475a004. If you are interested and unable to download a copy for yourself I can provide one.

Lecture 7

(updated for 2023)
  1. this is an interactive problems class, the answers are here pdf
  2. resources related to this lecture optional
    • where do the starting symmetry adapted orbitals come from? notes from a lecture: pdf
    • Reading: An old problems class The MO diagram of PL5 pdf

Assignment

(updated for 2023)
  1. Symmetry and Bonding Assignment handout: pdf
  2. Average mark 52%
  3. Model Answer: pdf
  4. in response to requests at the tutorial here is a sketch of the symmetry elements for the molecules in Q1: pdf
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