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Phase Diagrams

Phase Diagrams. Reading Phase Diagrams. Describing Phase Diagrams. Phase Boundary (boundary between phases) Triple Point (when three phases co-exist) Critical Point (where the properties of two phases become indistinguishable from each other) Fusion/Melting (s  l)

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Phase Diagrams

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  1. Phase Diagrams

  2. Reading Phase Diagrams

  3. Describing Phase Diagrams Phase Boundary (boundary between phases) Triple Point (when three phases co-exist) Critical Point (where the properties of two phases become indistinguishable from each other) Fusion/Melting (s  l) Evaporation (l  g) Condensation (g l) Sublimation (s  g) Desublimation (g  s) and Freezing( l  s)

  4. Phase Diagram of H2O Supercritical phase Critical point

  5. Supercritical Water Beyond the critical point in the liquid-vapor space, water is supercritical existing as small but liquid-like hydrogen-bonded clusters dispersed within a gas-like phase

  6. Supercritical Water The properties of supercritical water are very different from ambient water. For example, supercritical water is a poor solvent for electrolytes; however, it is such an excellent solvent for non-polar molecules, due to its low dielectric constant and poor hydrogen bonding, that many organic substances are completely miscible.

  7. Phase Diagram of CO2

  8. Supercritical Systems Supercritical carbon dioxide is used to extract molecules from plants for pharmaceuticals. Supercritical water is used to remove toxic waste from contaminated soil. And some believe supercritical fluids could be used to extract magnesium from rocks on Mars to make rocket fuel.

  9. Phase Diagram of UF6Name the name of the process in the boxes UF6

  10. Crystallography crystalline (non-amorphous) Powder (amorphous)

  11. Single crystal diffractometry Video recorder N2(liq or gas) injector CCD Detector

  12. Single-crystal

  13. Bragg’s Law nl = 2d sinq (1) l =1.54Å (of X-ray) Rays striking atoms in the second layer travel a distance equal to BC +CB' farther than rays striking atoms in the first layer. If this distance is a whole number of wavelengths, the reflected rays are in-phase and interfere constructively. Knowing the angle q then makes it possible to calculate the distance d between the layers.

  14. Electron Density Map

  15. Crystal Packing Crystals are three dimensional ordered structures than can be described as a repetition of identical unit cells. The unit cell is made up of the smallest possible volume that when repeated, is representative of the entire crystal. Unit Cell

  16. The dimensions of a unit cell can be described with 3 edge lengths (a,b,c) and 3 angles (alpha, beta, gamma).

  17. Space Groups

  18. Packing of Inorganic Simple Salts (spheres)

  19. YBa2Cu3O7+x Superconductivity is the tendency of a material to conduct electricity without any resistance . Meissner Effect

  20. ZrZn2

  21. Two crystals of Iron

  22. Iron using Scanning Tunnel Microscopy

  23. 1X10-9 m = 1 E-9 m= 1 nm = 10 Å = 1000 pm NaCl Calculate density in g/cm3

  24. Calculate the cell edge length in pm of the unit cell of Cu, which crystallizes in Face Center Cube lattice and has a density of 8.96g/cm3

  25. HW Due Feb 7 EXAM 1 on Feb 7

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