Fepo4 Case Study
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In the study conducted by Haines, Cambon & Hull (2003), they examined the impact of temperature change from 294 to 1073K on the structural development of FePO4. Initially, at low temperature, FePO4’s structure is of tetrahedral. This α-quartz structure is illustrated in the following diagram. However, as temperature increases, the tilting of the tetrahedral angles began to drop. This continues as it approaches 980K to the β-phase, where it gradually forms an octahedral structure. In the early structure transition, discontinuities are easily identified. Temperature starts to increase during α-phase. At this stage, although the dependency is not linear, the cell parameters and volume increase tremendously. The coefficient of the …show more content…
It holds PO4 tetrahedrons, which is essential to help decide the structural properties. The distortion of the tetrahedral is believed to be due to the tilt angle δ and the intertetrahedral bridging angle θ. Furthermore, at higher temperature, the O-PO angle and the change in bond length are also possible contributors to the distortion of the tetrahedral. However, up till this stage, it is still reasonable to view the tetrahedrons as a firm body. This is because the tilt has a more significant role in establishing the distortion of the tetrahedral. All in all, the distortion is due to the tilt, which is reliant on the temperature. For quartz-type FePO4 in the α-phase, the volume and cell parameters experience a rapid increase. The main contributor to the expansion of thermal is the angular variations caused by the modifications of the tilt angles and the two symmetrically-independent intertetrahedral Fe-O-P bridging angles. The temperature reliance of this angle is illustrated using the Landau-type model: δ2 = 2/3 δ02 [1 + (1 – ¾ (T – Tc/T0 – Tc))^1/2]. δ0 represents the decline in the angle of tilt during the temperature transition (980K), while the Tc represents the second order transition’s temperature. A fine fit to δ4 for FePO4 is derived by squaring this equation. At the transition from α to β phase, the atomic coordinates and cell parameters from the α-phase lean towards those in the β-phase. There are important changes of angles and distance of the bonds. Specifically, it is evident that the quartz transition from α to β phase can be modelled with a single order parameter, the tilt angle
In the study conducted by Haines, Cambon & Hull (2003), they examined the impact of temperature change from 294 to 1073K on the structural development of FePO4. Initially, at low temperature, FePO4’s structure is of tetrahedral. This α-quartz structure is illustrated in the following diagram. However, as temperature increases, the tilting of the tetrahedral angles began to drop. This continues as it approaches 980K to the β-phase, where it gradually forms an octahedral structure. In the early structure transition, discontinuities are easily identified. Temperature starts to increase during α-phase. At this stage, although the dependency is not linear, the cell parameters and volume increase tremendously. The coefficient of the …show more content…
It holds PO4 tetrahedrons, which is essential to help decide the structural properties. The distortion of the tetrahedral is believed to be due to the tilt angle δ and the intertetrahedral bridging angle θ. Furthermore, at higher temperature, the O-PO angle and the change in bond length are also possible contributors to the distortion of the tetrahedral. However, up till this stage, it is still reasonable to view the tetrahedrons as a firm body. This is because the tilt has a more significant role in establishing the distortion of the tetrahedral. All in all, the distortion is due to the tilt, which is reliant on the temperature. For quartz-type FePO4 in the α-phase, the volume and cell parameters experience a rapid increase. The main contributor to the expansion of thermal is the angular variations caused by the modifications of the tilt angles and the two symmetrically-independent intertetrahedral Fe-O-P bridging angles. The temperature reliance of this angle is illustrated using the Landau-type model: δ2 = 2/3 δ02 [1 + (1 – ¾ (T – Tc/T0 – Tc))^1/2]. δ0 represents the decline in the angle of tilt during the temperature transition (980K), while the Tc represents the second order transition’s temperature. A fine fit to δ4 for FePO4 is derived by squaring this equation. At the transition from α to β phase, the atomic coordinates and cell parameters from the α-phase lean towards those in the β-phase. There are important changes of angles and distance of the bonds. Specifically, it is evident that the quartz transition from α to β phase can be modelled with a single order parameter, the tilt angle