Creative Chemistry Molecular Models

AS Level Chemistry Structures

What is here?

You need to know about the bonding and structure of four different substances: sodium chloride, iodine, diamond, and graphite. The table below summarises these details, and the molecular models let you examine the structures in detail.
 

substance	NaCl	iodine	diamond	graphite
bonding	ionic	covalent	covalent	covalent
structure	giant ionic lattice	simple molecular	giant molecular	giant molecular
physical properties	High melting and boiling point. Hard and brittle. Soluble in water. Conducts electricity when molten or in solution.	Low melting point. Soft, shiny black solid which forms a purple vapour. Low solubility in water. Does not conduct electricity.	Very high melting and boiling point. Hard and brittle. Insoluble in water. Does not conduct electricity.	Very high melting and boiling point. Soft and brittle. Insoluble in water. Conducts electricity.
notes	Each sodium ion is surrounded by six chloride ion, and each chloride ion is surrounded by six sodium ions (it has 6:6 coordination).	Each molecule comprises two iodine atoms joined by a covalent bond. The molecules in solid iodine form a regular array with weak van der Waal's forces between molecules.	Each carbon atom is covalently bonded to four other carbon atoms in an extended tetrahedral arrangement.	Each carbon atom is covalently bonded to three other carbon atoms to form layers of atoms in a hexagonal arrangement. Delocalised electrons above and below each layer. Weak van der Waal's forces between layers.
substance	NaCl	iodine	diamond	graphite

back to top

The models are shown as wire-frames to begin with. You can move the models using the left mouse button. Right click to get a menu of options to try, such as changing to space-filling models.
 

Molecular modelling applet courtesy of ChemAxon Ltd

(YOU CANNOT SEE A JAVA APPLET HERE)

back to top