From the research paper, the structure of FePO4 is being studied from a temperature range of 294K to 1073K by neutron powder diffraction. When heated to a higher temperature, both the crystal structure of SiO2 and FePO4 have a higher tendency to undergo a first order transition of the F"# transition as compared to #FFePO4. SiO2 has a space group of P3121 where it has a lattice symmetry of a tetrahedral shape. As for FFePO4, which is mainly found in low temperature, has a space group of P3121 with a tetrahedral structure which is similar to that of SiO2. However, as for #FFePO4, it has a space group of P6422 with an octahedral structure and it is mainly found in high temperature. Comparing all 3 structures, SiO2 has a similar space group and lattice symmetry with FFePO4. …show more content…
This can be illustrated with this alterFbound equation: $%&' + )*' → 2-./'. The transition occurs at 980K where there will be significant changes in bond distances and angles due to the change in the polymorphic form. As the temperature increases, FFePO4 will have a significant increase in cell volume and cell parameters. This is so as the change in volume is controlled by the values of 0 and 1 as a function of temperature. However, the dependency is not linear. Moreover, FFePO4 has greater angular variations and the values of cell parameters and fractional atomic coordinates have a tendency towards the high temperature # phase of FePO4. The degree of distortion of the structure of #FFePO4 is represented by the tetrahedral tilt angle 0=0° and intertetrahedral bridging angle 1 = 154°. Since the values of 1 > 136° and 0 < 22°, it is believed that the F"# transition will not be
To remove the impurity, the fluorene had to be recrystallized and purified. In an aside step, 15 mL of ethanol was heated until the solvent was boiling. Ethanol is the ideal solvent to crystallize fluorene, because it is polar. Though fluorene is nonpolar, fluorene is not too soluble or insoluble in ethanol. The decision for selecting this solvent came from past experimentations as well. At first, methanol would have been a good solvent for fluorene, but methanol evaporates very quickly. A greater amount of methanol would have been required to dissolve the impure fluorene, but a little amount of ethanol is only needed to dissolve the impure fluorene completely. Once the ethanol solvent was boiling, a small amount was added to the flask, just enough to cover the impure fluorene solids. That flask was then heated on a hot plate, and additional hot ethanol was added continuously until the fluorene completely dissolved (10). As soon as the solid dissolved, the flask was stoppered and placed into an ice-water bath (11). Crystallization happened almost
Physical Chemistry Laboratory Manual, Physical Chemistry Laboratory, Department of Chemistry, University of Kentucky, Spring 2006.
Scibd. N.p. Web. 17 Mar 2014. Beller, Michele.
The objective of this lab is to find the equilibrium constant of Fe(SCN)2+ through multiple trials using a spectrometer. Since one chemical is colorless and the other is colored a spectrometer can be used to monitor amounts of each in the solution. By completing multiple trials an average can be reached for the value of the equilibrium constant of Fe(SCN)2+.
Sulfites don’t cause problems for the vast majority of people, but about one in every hundred people is sensitive or allergic to them.
In order to understand the controversy of fluoride, one must know the background . Fluoride is the ionic form of the element fluorine, an element abundant in the earth's crust (Borso 23). Fluoride is shown that is
The IUPAC defined polymorphic transition as “A reversible transition of a solid crystalline phase at a certain temperature and pressure (the inversion point ) to another phase of the same chemical composition with a different crystal structure” .
Sulfur Natarsha Harris Introduction to Chemistry Professor Michael Jones June 7, 2017. Sulfur goes back to the ancient times, but it was called brimstone. In 1979, a French chemist named Antoine Lavoisier recognized sulfur was an element and added it to his list of elements. The element sulfur is considered a nonmetal and is the 10th most abundant element in the universe. On the periodic table, sulfur is in group sixteen
The expected melting point of Semicarbazone of Cyclohexanone is 166°C.1 The assumed product is Semicarbazone of Cyclohexanone. Observed temperature being lower than the expected may indicate a contamination or an impurity. The low temperature result was shown to be more accurate than the room temperature result. Perhaps, in the room temperature, there was more of a mix in the products (i.e. containing both Semicarbazone of Cyclohexanone and Furaldehyde). This is reinforced by the pale yellow colour observed, when Semicarbazone of Cyclohexanone is supposed to be white. Room temperature result could be close to the eutectic point. This is kinetic control, as it is formed much quicker than the product of the high temperature reaction. To fix the problem of lower than expected melting point could be have a set temperature as to how cold the low temperature should be (e.g.
In order to gain strong insight into the surface chemistry of silica we have perform a thorough literature search. Our goal is to identify the pioneer research performed on silica and silica supported catalyst. Particular interest lies in silica-water-cobalt and silica-alcohol-cobalt systems. This study is both on macro and micro level so that a complete theoretical base can be established. From this theoretical knowledge, key areas to look upon will be identified and a design of experiments will be established. The goal is to develop a both efficient and effective product (catalyst) using a novel methodology developed from past research.
Iron comes from the Latin word ferrum. From ferrum its symbol became Fe. The atomic number of iron is 26, and its atomic weight is 55.845. Iron is a magnetic, bendable, shiny white metallic element.
23. S. Alwarappan, S. Boyapalle, A. Kumar, C.-Z. Li and S. Mohapatra, J. Phys. Chem. C, 2012, 116, 6556–6559
BACKGROUND Types of Silica Crystalline silica may be of several distinct types. Quartz, a form of silica and the most common mineral in the earth's crust, is associated with many types of rock. Other types of silica include cristobalite and tridymite. Potential for Exposure During Construction Concrete and masonry products contain silica, sand and rock containing silica. Since these products are primary materials for construction, construction workers may be easily exposed to respirable crystalline silica during activities such as the following: Chipping, hammering, and drilling of rock Crushing, loading, hauling, and dumping of rock   high dust concentrations.
At this point the desirable crystalline structure of the metal has been reached but it must not be allowed to be heated further as the solution will begin to melt.
Chemical reactions involve the making and breaking of bonds. It is essential that we know what bonds are before we can understand any chemical reaction. To understand bonds, we will first describe several of their properties. The bond strength tells us how hard it is to break a bond. Bond lengths give us valuable structural information about the positions of the atomic nuclei. Bond dipoles inform us about the electron distribution around the two bonded atoms. From bond dipoles we may derive electronegativity data useful for predicting the bond dipoles of bonds that may have never been made before.