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-SulfurOther elements that adopt this structure: none.
A unit cell of α-polonium is shown to the left. Only the corner positions are occupied with polonium atoms. Note that the unit cell corners are in the centres of the polonium atoms. This means that only one eighth of the corner atom is actually inside a given unit cell. Therefore the total atom occupancy inside a unit cell is equal to (8 x 1/8) = 1. This can be appreciated fully by looking at the structure on the next page. It is evident from the unit cell that all polonium atoms in the structure are in equivalent positions.
Go to page 4 to look at how the unit cells stack together to yield the bulk structure of α-polonium.