1. Structure and Bonding
Why are we interested in structure and bonding?

2. It answers all these questions and more………..
Why is salt brittle?
Why is ammonia a gas?
Why does iodine sublime?
Why are diamonds so hard and shiny?

3. Introducing x-ray crystallography
Where did it all start?
Sir Lawrence Bragg ( ) found x-rays could be used to decipher crystal structures
Introducing x-ray crystallography
X-ray wavelengths similar to the distance between atoms in a crystal.
The atoms or ions scatter the x-rays, giving a diffraction pattern.
The diffraction pattern is then used to deduce the 3-D crystal structure
P63 fig

5. Sodium chloride

6. Chemical Structures and Chemical Bonding
Atoms are the building blocks of all substances
chemical bonding
LARGER structures
Elements if all bonded atoms same
Compounds if 2 or more different atoms bonded
(except noble gases)
SIMPLE MOLECULAR structures
GIANT structures
Low melting point solids
Liquids
Gases
eg I2 , P4
eg Br2, H2O
eg H2, O2, CO2, NH3
High melting point solids ONLY
eg Diamond, graphite, NaCl, Cu, SiO2 etc
May be covalent or ionic or metallic bonding
ALL covalent bonding