The lattice symmetry of quartz α-FePO4 is trigonal. Its space group is P3121. The lattice symmetry of quartz β-FePO4 is hexagonal. It space group is P6422.
According to the article, only two of the various quartz homeotypes which exhibit alpha-beta transitions have been studied in detail at high temperature. One of them is Silicon Dioxide. As such, it is possible for silicon dioxide to have the same structure when the chemistry is completely different.
Since iron is trivalent and phosphorus is pentavalent, an equation of the following can be written to explain the chemical substitution which takes place to maintain the same symmetry:
Here, the total charge on each side has a charge of 8+ and …show more content…
For example, as temperature increases, the degree increases as well. At a temperature of 294K, the θ average is 137.9 degree and at a temperature of 465K, θ becomes 140.0 degree. The temperature dependence of the volume strongly follows the behavior of the average θ as a function of temperature.
The relationship between the unit cells is as follow:
Both are seen from the C axis. These results show that α- FePO4 has a trigonal unit cell whereas β- FePO4 has a hexagonal unit cell. In both cases, the actual dimensions remain the same. This is despite the change in temperature. The dimensions remain the same even though there is a change in symmetry.
The symmetrical differences between α-FePO4 and β-FePO4 are that α-FePO4 is trigonal and β-FePO4 is hexagonal. When temperature increases, the volume expands. The tilt angle, δ, has an inverse relationship with temperature. As temperature approaches the alpha to beta phase, the tilt angle decreases. This can be attributed to the increasing disorder at high temperature arising from excited low energy, high
amplitude
According to the article, only two of the various quartz homeotypes which exhibit alpha-beta transitions have been studied in detail at high temperature. One of them is Silicon Dioxide. As such, it is possible for silicon dioxide to have the same structure when the chemistry is completely different.
Since iron is trivalent and phosphorus is pentavalent, an equation of the following can be written to explain the chemical substitution which takes place to maintain the same symmetry:
Here, the total charge on each side has a charge of 8+ and …show more content…
For example, as temperature increases, the degree increases as well. At a temperature of 294K, the θ average is 137.9 degree and at a temperature of 465K, θ becomes 140.0 degree. The temperature dependence of the volume strongly follows the behavior of the average θ as a function of temperature.
The relationship between the unit cells is as follow:
Both are seen from the C axis. These results show that α- FePO4 has a trigonal unit cell whereas β- FePO4 has a hexagonal unit cell. In both cases, the actual dimensions remain the same. This is despite the change in temperature. The dimensions remain the same even though there is a change in symmetry.
The symmetrical differences between α-FePO4 and β-FePO4 are that α-FePO4 is trigonal and β-FePO4 is hexagonal. When temperature increases, the volume expands. The tilt angle, δ, has an inverse relationship with temperature. As temperature approaches the alpha to beta phase, the tilt angle decreases. This can be attributed to the increasing disorder at high temperature arising from excited low energy, high
amplitude