Iron And Feipo4 Reaction Lab Report

945 Words 4 Pages
Compare and contrast the crystal structures and crystal chemistry of quartz, α-FePO4 and β-FePO4.
FePO4 is also known as Iron (III) phosphate. Iron (III) phosphate is an inorganic compound. Most of the FeP04 has the structure of α-quartz which is α-FePO4. It has a tetrahedral molecular geometry. α-FePO4 is present at pretty low degree Celsius. It is also a transition metal as it is in the d-block in the periodic table. It can be studied at many different temperature which range from 294K to 1073K with the use of neutron powder diffraction. When there is an increase in pressure, it will lead to a phase change. This causes the octahedral Fe centres to become denser. It will thus lead to the formation of β-FePO4. This transition of α-FePO4 to
…show more content…
The tilt angle continues to decrease when the temperature increases. This shows that they have a negative correlation.
Describe changes in the FeO4 and PO4 tetrahedral with temperature and explain tetrahedral tilting quantitatively. When α - β transition takes place at 980K, the structural integrity and properties depends significantly on the PO4 tetrahedrons. The tilt angle is one of the significant factor which will lead to tetrahedral distortion. Tetrahedral distortion occurs when there is a change in the angle and also the change in the length of the bonds. The tilt angle as mentioned in paragraph 2 above, is inversely correlated with temperature. Another factor which led to tetrahedral distortion is due to the change in bond length and the change in O-PO angle which defers according to temperature. This means that when the temperature reaches roughly about 980K, the Fe—O—P bridging angles will increase and the tilt angles will decrease strongly. For the quartz-type FePO4, the bond distance and volume of the phase increases significantly and non-linearly as a function of temperature. The temperature dependence of this tilt angle can be reflected using Landau-type model expressed as

Related Documents