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Solid State Synthesis, Phase Diagrams and Solid Solutions

Solid State Synthesis, Phase Diagrams and Solid Solutions

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Solid State Synthesis, Phase Diagrams and Solid Solutions

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

  2. Grind 2 Heat 4 3 Repeat Grind & Heat Solid State Reactions Example: MgO(s) + MoO3(s)  MgMoO4 1 Micron Sized Powders (Starting Materials)

  3. Two Component Phase Diagram D Liquid Liquid C) C) Eutectic Point Eutectic Point ° ° MgS ( ( ss ss ) + ) + A ZnS ( ss ) Liquid Liquid Temperature ( Temperature ( ZnS ( ( ss ss ) + ) + Liquid Liquid MgS ( ( ss ss ) ) 2 2 - - phase region phase region C MgS ( ( ss ss ) + ) + ZnS ( ( ss ss ) ) B 0 0 25 25 50 50 75 75 100 100 Mole % Mole % ZnS Pure Pure MgS Pure Pure ZnS

  4. Region A Region C Region B Microscopic View Microscopic View Microscopic View Homogeneous Solid Solution Mg0.8Zn0.2S Homogeneous Solid Solution Mg0.1Zn0.9S Two phase (heterogeneous) mixture Mg0.8Zn0.2S + Mg0.1Zn0.9S How can we analyze materials to determine their composition and heterogeneity. Zinc Blende type Zn1-xMgxS Rock salt type Mg1-xZnxS

  5. Incoming X-ray photon 2 3 1 Emitted photon ejected e− X-ray Fluorescence 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. N shell n = 4 M shell n = 3 Energy L shell n = 2 Lα Lβ K shell n = 1 Kα Kβ