Types and properties of inorganic crystalline materials

Question 1

Describe metallic structures

Answer 1

Bonds are reasonably strong, as shown by metals having high melting points. Atoms are surrounded by a sea of electrons.

Question 2

Describe covalent solids

Answer 2

Eg graphite or diamond. Solids in which all bonding is covalent - characterised by a build up of electron density

Question 3

Describe ionic solids

Answer 3

Eg NaCl. The solid contains ions rather than uncharged atoms. The predominant interaction between the ions is electrostatic

Question 4

Describe a molecular structure

Answer 4

Eg ice. Discrete, uncharged and covalently bonded molecules are held together through London forces, sometimes hydrogen bonds. Bonding is quite weak, so melting temperatures are relatively low.

Question 5

Describe a molecular ionic material

Answer 5

Molecules in these solids bare a charge and so the electrostatic forces dominate and give rise to reasonably thermally stable materials, eg CaCO3