The diagrams represent the structures of two allotropes of carbon, X (a 3-D network of atoms each joined to four others) and Y (flat layers of hexagons stacked above each other).

1. aIdentify allotrope X. [1]
2. bIdentify allotrope Y. [1]
3. cGive one use of any of the allotropes and state the physical property upon which this use depends. [2]

You'll mark your own answer against the marking guide when you hand it in.