CHEM 171-1: Molecular Orbitals and Lewis Structures

Include angles with lone pairs and not

Lowest Energy Pi Orbitals (1pi)

All 2p_z’s in phase; an angular node (planar node)

Highest Energy Pi Orbitals (4pi)

All neighbors out of phase; 3 nodes perpendicular to plane of molecule and still 1 node that is the same as 1pi

Intermediate Energy Pi Orbitals (2pi)

Net bonding; degenerate states; 1 node perpendicular to plane of molecules and still 1 node that is the same 1pi

Intermediate Energy Pi Orbitals (3pi)

Net antibonding; degenerate states; 3 nodes

Octahedral (6) Linear Combinations of Atomic Orbitals

Tetrahedral (4) Linear Combinations of Atomic Orbitals

Linear

2 electron domains; 0 lone pairs; 180 degrees

Trigonal Planar

3 electron domains; 0 lone pairs; 120 degrees

Bent 1

3 electron domains; 1 lone pair; slightly less than 120 degrees

Tetrahedral

4 electron domains; 0 lone pairs; 109.5 degrees

Trigonal pyramidal

4 electron domains; 1 lone pair; around 107.5 degrees

Bent 2

4 electron domains; 2 lone pairs; slightly less than 109.5 degrees

Trigonal Bipyramidal

5 electron domains; 0 lone pairs; 120 degrees and 90 degrees

Sawhorse

5 electron domains; 1 lone pair; less than 120 degrees and 90 degrees

T-Shaped

5 electron domains; 2 lone pairs; around 120 degrees and 90 degrees

Linear (trigonal bipyramidal)

5 electron domains; 3 lone pairs; around 120 degrees and 90 degrees

Octahedral

6 electron domains; 0 lone pairs; 90 and 180 degrees

Square pyramidal

6 electrons domains; 1 lone pair; around 90 and 180 degrees

T-shaped

6 electron domains; 3 lone pairs; around 90 and 180 degrees

Linear (octahedral)

6 electron domains; 4 lone pairs; around 90 and 180 degrees