Compare And Contrast The Crystal Structures And Crystal Chemistry Of Quartz, Α-Fepo4

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(Compare and contrast the crystal structures and crystal chemistry of quartz, α-FePO4 and β-FePO4.
Fully describes the crystallochemical relationships between the structures and the temperature dependence of polymorphism. )

This article focuses on the chemical structure of FePO4 between 294K and 1073K of thermodynamic scale, through high accuracy x-ray diffraction experiments. From the relatively lower temperature range, it acquires the chemical arrangement of an α-Quartz trigonal as shown below. However, as temperature steadily rises, there exists a series of minor changes, such as β-Tridymite hexagonal change at 870 °C. Hydrated amorphous FePO4 was synthesized in which a solution of (NH4)2HPO4 and FeSO4·7H2O was irradiated by an ultrasonic wave. Materials prepared are: (1) an amorphous sample prepared by heating …show more content…

The degree of destruction with respect to the beta quat structural type can be related to tetrahedral tilt angle delta and the intra-tetrahedral reaching angle theta. However, another condition, the delta value is greater than 22 degrees and theta value is less than 136 degrees. The alpha beta transition is not observed for most of the material. Yet, the structural property of FePO4 lie close above the limiting value. As an example of how FePO and PO angles and the length are actually changing as the temperature increases, FePO for the bond length in a tetrahedral bond angle, in a quartz type FePO4 as a structure, as a function of the temperature. As the temperature increase on 294 to 969, it is observed that FePO decrease in the length and subsequently, the angle of FePO2 is also smaller.This results in a change in the unit cell size, and the volume. It is in contrast to PO4, where there is an increase in temperature, resulting in compression, and subsequently the bond angle drops as well. This may be related to the overall tilt

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