Lesson09 - Pairwise Orbital Combinations Adopt a convention...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Pairwise Orbital Combinations Adopt a convention for combining orbital pairs Identify all the sigma-type combinations Cylindrical Symmetry: The top and bottom of a cylindrically symmetrical object may be different, but everything is the same around its cylindrical axis. Sigma orbitals have cylindrical symmetry SHEET #1 - The Pairwise Orbital Combinations z x y z x y z x y z x y z x y z x y z x y z x y z x y z x y z x y z x y z x y z x y z x y z x y x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x atom 2 atom 1 Instructions : (Part 1) For each symmetry- allowed combination, draw the orbital that results when the two atoms are brought together along the the x-axis (calling the internuclear axis the x-axis). See the example below: z x y z x y atom 1 atom 2 x 2s 2s 2p z 2p z 2p y 2p y 2p x 2p x 2s 2s 2p x 2p x 2p y 2p y 2p z 2p z atom 1 atom 2 Bringing orbitals together from two different atoms making MOs some orbital combinations interact in such a way as to c o n c e n t r a t e the electron density between the nuclei ( bonding interactions ) some orbital combinations interact in such a way as to d e p l e t e the electron density between the nuclei ( antibonding interactions ) some orbital combinations interact in such a way as to neither concentrate nor deplete the electron density between the nuclei ( nonbonding interactions ) See: Molecular Orbitals (N 2 ) at http://www.shef.ac.uk/chemistry/orbitron/ Instructions : (Part 2) Draw an outline around the group of orbital combinations that are n o t allowed to interact because of symmetry reasons. Write the label "symmetry forbidden" in large letters inside this zone. Instructions : (Part 3) For each allowed combination, add one of the following labels ( s , s *, p , p *, s/p , s/p *, ! y , ! y *, ! z , ! z *) where * denotes an antibonding interaction. SHEET #1 - The Pairwise Orbital Combinations z x y z x y z x y z x y z x y z x y z x y z x y z x y z x y z x y z x y z x y z x y z x y z x y x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x atom 2 atom 1 Instructions : (Part 1) For each symmetry- allowed combination, draw the orbital that results when the two atoms are brought together along the the x-axis (calling the internuclear axis the x-axis). See the example below: z x y z x y atom 1 atom 2 x 2s 2s 2p z 2p z 2p y 2p y 2p x 2p x 2s 2s 2p x 2p x 2p y 2p y 2p z 2p z atom 1 atom 2 Bringing orbitals together from two different atoms making MOs some orbital combinations interact in such a way as to c o n c e n t r a t e the electron density between the nuclei ( bonding interactions ) some orbital combinations interact in such a way as to d e p l e t e the electron density between the nuclei ( antibonding interactions ) some orbital combinations interact in such a way as to neither concentrate nor deplete the electron density between the nuclei (...
View Full Document

Page1 / 22

Lesson09 - Pairwise Orbital Combinations Adopt a convention...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online