1. Solid State Synthesis, Phase Diagrams and Solid Solutions Chemistry 123 Spring 2008 Dr. Woodward

2. Solid State Reactions Micron Sized Powders (Starting Materials) Example: MgO(s) + MoO 3 (s)  MgMoO 4 1 Grind 2Heat 3 Repeat Grind & Heat 4

3. Two Component Phase Diagram Mole %ZnS 0255075100 Liquid 2-phase region MgS(ss) +ZnS(ss) MgS(ss) + Liquid ZnS(ss) + Liquid MgS(ss) ZnS(ss) Temperature (  C) PureZnSPureMgS A B C Eutectic Point D Mole % 0255075100 Liquid 2-phase region (ss) +(ss) ( ) + Liquid (ss) + Liquid (ss) Temperature (  C) Pure Eutectic Point

4. Rock salt type Mg 1-x Zn x S Zinc Blende type Zn 1-x Mg x S Microscopic View Region ARegion BRegion C Microscopic View Homogeneous Solid Solution Mg 0.8 Zn 0.2 S Homogeneous Solid Solution Mg 0.1 Zn 0.9 S Two phase (heterogeneous) mixture Mg 0.8 Zn 0.2 S + Mg 0.1 Zn 0.9 S How can we analyze materials to determine their composition and heterogeneity.

5. X-ray Fluorescence Incoming X-ray photon ejected e − 1 Emitted photon 23 Principle Quantum # SubshellsElectron Shell Label # of Electrons in Shell 11sK2 22s, 2pL8 33s, 3p, 3dM18 44s, 4p, 4d, 4fN32 Because the energy levels between different shells change from element to element (because the effective nuclear charge is changing) the energy of the secondary X-rays that are emitted are different for each element. By measuring the energies of the secondary X-rays we can determine which elements are present and their approximate ratios.

6. KαKαKβKβ LαLαLβLβ Energy K shell n = 1 L shell n = 2 M shell n = 3 N shell n = 4