Beauty Form and Symmetry
Paragraph 1: Temperature; driver for the change of symmetry
There are 3 different phases that are observed and each of them are influenced by temperature. In addition, in each phase, the polymorph exhibits different crystal structures. At room temperature of 298K, it will be in phase 3 where it takes the structure of monoclinic-C2/m. When the temperature rises to 396K, it undergoes a transition into Phase 2 also known as the high-temperature monoclinic-A2/a phase. At Phase 2, the lattice parameters are a2=11.037(1)Å, b2=6.415(1)Å, C2=16.042(4)Å, β2=102.69(1)°,where Z=4. There is no reflective or rotational symmetry present at this temperature. There is twice the amount of hydrogen bonds compared to Phase 3, and the crystal structure has an inversion center about a 2-fold rotational axis, as well as a 2 fold twist axis. At Phase 2, because crystal symmetry is compromised, the temperature has allowed for a flexible crystal structure to allow for protons to move, and because it is not suppressed by any hydrogen bonds like in Phase 1 (298K room temperature). The last transition will happen when the temperature crosses above 456K. This final phase in transition takes the crystal structure of trigonal with space group of R3-m. Clearly, as temperature rises, the thermal energy increases, causing the atoms to have greater thermal kinetic energy to vibrate at higher frequencies. This results in higher disorder amongst the atoms and hence, lowers symmetry. The relationship between temperature and atom symmetry is inverse; the higher the temperature, the lower the symmetry.
Paragraph 3:
Proton mobility is a pre-requisite for superprotonic conductivity. So unlike most materials, the Cs3H(SeO4)2 crystal’s degree of symmetry decreases as the temperature increases above 396K, causing it to change from Phase III to Phase
II. During this transition, the orientation of the hydrogen bonds changes to face a
[310]/[3Ī0] direction from an initial position that is
There are 3 different phases that are observed and each of them are influenced by temperature. In addition, in each phase, the polymorph exhibits different crystal structures. At room temperature of 298K, it will be in phase 3 where it takes the structure of monoclinic-C2/m. When the temperature rises to 396K, it undergoes a transition into Phase 2 also known as the high-temperature monoclinic-A2/a phase. At Phase 2, the lattice parameters are a2=11.037(1)Å, b2=6.415(1)Å, C2=16.042(4)Å, β2=102.69(1)°,where Z=4. There is no reflective or rotational symmetry present at this temperature. There is twice the amount of hydrogen bonds compared to Phase 3, and the crystal structure has an inversion center about a 2-fold rotational axis, as well as a 2 fold twist axis. At Phase 2, because crystal symmetry is compromised, the temperature has allowed for a flexible crystal structure to allow for protons to move, and because it is not suppressed by any hydrogen bonds like in Phase 1 (298K room temperature). The last transition will happen when the temperature crosses above 456K. This final phase in transition takes the crystal structure of trigonal with space group of R3-m. Clearly, as temperature rises, the thermal energy increases, causing the atoms to have greater thermal kinetic energy to vibrate at higher frequencies. This results in higher disorder amongst the atoms and hence, lowers symmetry. The relationship between temperature and atom symmetry is inverse; the higher the temperature, the lower the symmetry.
Paragraph 3:
Proton mobility is a pre-requisite for superprotonic conductivity. So unlike most materials, the Cs3H(SeO4)2 crystal’s degree of symmetry decreases as the temperature increases above 396K, causing it to change from Phase III to Phase
II. During this transition, the orientation of the hydrogen bonds changes to face a
[310]/[3Ī0] direction from an initial position that is