Phase 3 Lab Report

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When in different conditions Ce3H(SeO4)2 crystals show different properties, different temperatures will result the crystal to change its phase. At RTP, the crystal will be in mono clinic (C2/m) phase which is Phase III. The crystal has a lattice structure of a=10.903 (3) Å, b=6.3904 (8) Å, c=8.452 (2) Å and α=γ=90 degree, β=102.69 (1) degree. When at the temperature of 470K it will exist in trigonal (R-3m) phase (Phase I). Where it will have lattice structure of a=b= 6.4260 (6) Å, c=23.447 (2) Å and α=β=90 degree, γ=120 degree. In Phase III/II the temperature boundary is at 369K and at Phase II/I temperature will be at 456K. Phase III, There are hydrogen bonds that are bonded along the a-axis between the SeO4 tetrahedrons. The optimal distance for both hydrogen to bond on both side is due…show more content…
It will result the bond length to be change to [3 1 0] direction. Being in Phase I, the structure is changed till the oxygen that is involved in the optimal hydrogen bond is centralized in the middle of the tetrahedron. Therefore there are more optimal structures instead of having one only. It is also equally stable when tetrahedron can form hydrogen bonds with other tetrahedron next to it due the similar distance. The change of temperature will result in change of symmetry and also it will also measure the movement of particles in the structure. At lower temperature the particles will only vibrate in their own structure, where it will result in a very stable structure and it will be more rigid. In turn it

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