Phase diagrams for materials that have allotropes can be more complicated than those shown in the chapter. Use the phase diagram for carbon given here to answer the following questions.

(a) How many triple points are present and what phases are in equilibrium for each?
(b) Is there a single point where all four phases are in equilibrium?
(c) Which is more stable at high pressures, diamond or graphite?
(d) Which is the stable phase of carbon at room temperature and 1 atmosphere pressure?

Transcribed Image Text:

p/GPa 1000 100- 10 1 0.1- 0.01- 0.001 0 1 2 Diamond Graphite 3 4 5 6 T/1000 K Liquid Vapor 7 8 9 10