Iron III Phosphate Lab Report

965 Words 4 Pages
Symmetry Writing Exercise
Paragraph 1
The research paper written by J. Haines, O. Cambon and S. Hull aims to understand how Iron III phosphate (FEPO4) behaves under high temperatures and at which temperature would we start to observe structural transition of Iron III phosphate. As found by the researchers, the temperature where one is able to witness a structural change of Iron III phosphate, a transition from α-β would be at the temperature of 980K. As the researchers have highlighted, there have been substantial high temperatures experiments done on isotopes (AIPO4) and Quartz (SiO4). However there is a lack of experiments and information of how FEPO4 behaves under high temperature conditions. It is useful and important to understand the
…show more content…
Also, with the increase of temperatures, there was an observation of increasing kinetic energy, vibrations within Iron(III) phosphate that led the distance between tetrahedral Fe-O to contract. When the temperature reaches 980K, the researchers could conclude that 980K is the temperature that results in the transition of Iron(III) phosphate from α-FePO4 to β-FePO4. The symmetry structure of Iron(III) phosphate polymorphs is strongly linked to the temperature it is placed in. Prior to the temperature of 980K, we can see that the α-FePO4 state possesses a trigonal unit cell. When the temperature hits 980K, which has been concluded as the transition temperature, we can see that the symmetry of the unit cell of α-FePO4 has transition from trigonal to hexagonal reaching the β-FePO4 state. As Iron(III) phosphate approached the temperature stage of 980K, there were a number of things observed that results in the change of symmetry structure of Iron(III) phosphate. Firstly, there was a significant decline of the distances of Fe-O within Iron(III) phosphate which might be caused by the increasing activity brought about by the increasing temperature . Additionally, we can see that the original tetrahedral symmetry structure of Iron(III) phosphate was gradually breaking down with the altering angles and increase of cell parameters of the Iron(III) phosphate bonds. The Fe-O-P bond experienced an expansion, …show more content…
As Iron(III) phosphate approaches the temperature of 980K, where we can witness a transition from α-FePO4 to β-FePO4 there is the occurrence of tetrahedral distortion. There are 2 contributing factors that leads to tetrahedral distortion. The first being a change in tilt angles and second the inter-tetrahedral bridging angle θ. Additionally, the increasing temperature causes increased kinetic energy and activity in the atom, leading to changes in both bond length and the angles of tetrahedral PO4. When FeO4 approaches 980K, the bond length of Fe-O becomes smaller leading to a smaller angle, this decrease leads to the volume of the cell to shift. This is also faced by P-O where its length started to become smaller which naturally leads to a shrinking angle when temperatures starts to reach 980K. The tetrahedral distortion and structural transition from α-FePO4 to β-FePO4 rest heavily on the coordinates of O1 and O2 in the atom as the change in O1 and O2’s coordinates results in the change in tilt angles in FeO4 and PO4. The behavior observed in this experiment shows that FePO4 is unique from other α-quartz homeotype. What is unique of FePO4 is that, even when compared to SiO2 and AIPO4 that are considered as stable materials, the δ angle registers a much higher decrease. On the flip

Related Documents