Molecular Geometry

1. No heavy math includedNo heavy math included
Molecular GeometryMolecular Geometry

2. Shapes of Molecules
Molecular Structure or Molecular Geometry
-is the three-dimensional arrangement of the atoms that
constitute a molecule. It determines several properties
of a substance including its reactivity, polarity, phase of
matter, color, magnetism, and biological activity.
-the chemical formula has no direct relationship with the
shape of the molecule.

3. Shapes of Molecules
Molecular Structure or Molecular Geometry
-the three-dimensional shapes of molecules can be
predicted by their Lewis structures.
-Valence-shell electron pair repulsion (VSEPR) model or
electron domain (ED) model: Used in predicting the
shapes. The electron pairs occupies a certain domain.
They move as far as possible. Lone pairs occupies more
domains contributing largely to the repulsion and shape.

4. Terms and Definition
Bonding Pairs (AX)– electron pairs that are involved in
the bonding.
Lone Pairs (E)– electrons that are not involved in the
bonding. They tend to occupy a larger domain.
Electron Domains – total number of pairs found in the
molecule that contribute to its shape.

5. Linear
•Bonding Pairs: 2
•Lone Pairs: 0
•Electron Domains: 2
•Bond angle: 180°
•Example: CO
2

Image:

6. Trigonal Planar
•Bonding Pairs: 3
•Lone Pairs: 0
•Electron Domains: 3
•Bond angle: 120°
•Example: BF
3

Image:

7. Bent or Angular
•Bonding Pairs: 2
•Lone Pairs: 1
•Electron Domains: 3
•Bond angle: 120° (119°)
•Example: SO
2
Image:

8. Tetrahedral
•Bonding Pairs: 4
•Lone Pairs: 0
•Electron Domains: 4
•Bond angle: 109.5°
•Example: CH
4
Image:

9. Trigonal Pyramidal
•Bonding Pairs: 3
•Lone Pairs: 1
•Electron Domains: 4
•Bond angle: 109.5° (107.5°)
•Example: NH
3
Image:

10. Bent or Angular (Ver.2)
•Bonding Pairs: 2
•Lone Pairs: 2
•Electron Domains: 4
•Bond angle: 109.5° (104.5°)
•Example: H
2O
Image:

11. Trigonal Bipyramidal
•Bonding Pairs: 5
•Lone Pairs: 0
•Electron Domains: 5
•Bond angle: 90°, 120°
•Example: PCl
5
Image:

12. Seesaw
•Bonding Pairs: 4
•Lone Pairs: 1
•Electron Domains: 5
•Bond angle: 180°, 120° (173.1°, 101.6°)
•Example: SF
4
Image:

13. T-shaped
•Bonding Pairs: 3
•Lone Pairs: 2
•Electron Domains: 5
•Bond angle: 90°, 180° (87.5°, < 180°)
•Example: ClF
3
Image:

14. Linear
(Multiple Lone Pairs)
•Bonding Pairs: 2
•Lone Pairs: 3
•Electron Domains: 5
•Bond angle: 180°
•Example: XeF
2
Image:

15. Octahedral
•Bonding Pairs: 6
•Lone Pairs: 0
•Electron Domains: 6
•Bond angle: 90°
•Example: SF
6
Image:

16. Square Pyramidal
•Bonding Pairs: 5
•Lone Pairs: 1
•Electron Domains: 6
•Bond angle: 90° (84.8°)
•Example: BrF
5
Image:

17. Square Planar
•Bonding Pairs: 5
•Lone Pairs: 1
•Electron Domains: 6
•Bond angle: 90°
•Example: XeF
4
Image:

18. Pentagonal Bipyramidal
•Bonding Pairs: 7
•Lone Pairs: 0
•Electron Domains: 7
•Bond angle: 90°, 72°
•Example: IF
7
Image: