Resources written by Chas McCaw for sixth form chemistry teaching and beyond.
General interest:
Graphite Buckminsterfullerene Ice White phosphorus Benzene Cyclohexane AdamantaneCubic:
Sodium Caesium chloride Polonium Copper Halite Fluorite Antifluorite Zinc blende DiamondNon-cubic:
Hexagonal:
Magnesium WurtziteTetragonal:
RutileTrigonal:
α-quartzTriclinic:
Copper(II) sulfateOrthorhombic:
α-SulfurMonoclinic:
β-SulfurSince all the carbon atoms in diamond are bonded to four neighbours in a tetrahedral arrangement, we may also visualise the diamond structure in terms of linked tetrahedra. As you can see, there are atoms at the four corners of the tetrahedra, which are linked through their corner positions. There is also a carbon at the centre of each tetrahedron, bonded to the four atoms visible at the corners, but the carbon in the centre of each tetrahedron is not visible in the representation to the left. The edges of the tetrahedra represent carbon-carbon bonds.
Polyhedral representations are especially useful in depicting more complex structures. To the left is the tetrehedral representation of the diamond unit cell. You will need to rotate it to see how the tetrahedra relate to each other.
Go to page 11 to see a polyhedral representation of a cube of eight diamond unit cells.
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