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-SulfurBenzene is an aromatic hydrocarbon with chemical formula C6H6. It is a liquid under ambient conditions, and was first isolated from oil gas in 1825. It is carcinogenic and has been used, controversially, as a lead replacement in petrol to improve its octane rating.
In the structure to the left the carbon atoms are coloured grey and the hydrogen atoms white. The molecule is planar and there is a delocalised π system on the carbon atoms in the ring, giving each carbon-carbon bond a bond order of 1.5. The six-membered carbon ring is a regular hexagon, and so by symmetry the carbon atoms occupy equivalent positions. By virtue of this symmetry the six hydrogen atoms are also equivalent with each other. Note how a similar carbon unit is visible in graphite, except the carbons do not carry a hydrogen atom but are fused to form the lattice planes.
Go to page 2 to look at the unit cell within the bulk crystalline structure of benzene in the solid state.