Uranium tetra fluoride and zirconium tetra fluoride melt at 1035°C and 912°C, respectively. They form a continuous series of solid solutions with a minimum melting temperature of 765°C and composition x (ZrF.) = 0.77. At 900°C, the liquid solution of composition x(ZrF.) = 0.28 is in equilibrium with a solid solution of composition x (ZrF.) = 0.14. At 850°C the two compositions are 0.87 and 0.90, respectively. Sketch the phase diagram for this system and state what is observed when a liquid of composition x (ZrF.) = 0.40 is cooled slowly from 900°C to 500°c.