Compare and contrast the crystal structures and crystal chemistry of quartz, α-FePO4 and β-FePO4. Quartz (SiO2) is the second most abundant mineral on Earth and is of significant uses in both material and Earth sciences. Quartz crystals exist in polymorphs, which mean that the crystal structure of quartz will change depending on the temperature and pressure of the environment that the crystal is in. The crystal will be in its alpha-crystal form when the surrounding temperature and pressure is low. However, when exposed to intense temperature and pressure, it will convert to its beta-crystal form. This paper aims to look at the transition phase of the two different crystal structures using FePO4, a homeotype of quartz. Both quartz and FePO4 …show more content…
Polymorphism refers to the ability of the crystal to exist in different lattice structure depending on the environmental conditions. In this case, FePO4 displays two kinds of lattice structure depending on the temperature and pressure of the environment. As mentioned previously, FePO4 crystals exist in alpha-structure in low temperature and pressure and changes to beta-structure in high temperature and pressure. The temperature at which the FePO4 crystals change phase is around 980K. In the alpha structure, the tetrahedral is arranged such that the structure of the cell is trigonal and has a space group of P3221. The changes in the two symmetrically independent intertetrahedral Fe-O-P bridging angle and the correlated tilt angles is the main factor of the thermal expansion of the alpha structure. The volume and cell parameters of the alpha structure increases non-linearly as a function of temperature. The thermal expansion coefficient is found to be α (K-1) = 2.924 x 10-5 + 2.920 x 10-10 (T-300)2. As the temperature increase, the bond angles and the bond distance changes significantly especially as it increases towards the 980k where the structure will change from alpha to beta. As the temperature increase, the crystal structures realign to form the beta structure. The tetrahedral shifts such that the structure changes from trigonal to hexagonal and has a space group of p6222. It must be noted that there was no breaking of bonds and the atoms are still surrounded by the same neighbouring atoms. There is lesser symmetry in the beta structure as compared to the alpha structure. In addition, as the temperature rise, the bond distance between Fe and O in the tetrahedral actually increases, which corresponds to that of alpha quartz. This non-physical behaviour is most probably due to the increase in enthalpy of the atoms at high temperature, resulting in high amplitude and energetic vibrations. A fall in the time-averaged bond distance
In order to separate the mixture of fluorene, o-toluic acid, and 1, 4-dibromobenzene, the previously learned techniques of extraction and crystallization are needed to perform the experiment. First, 10.0 mL of diethyl ether would be added to the mixture in a centrifuge tube (1) and shaken until the mixture completely dissolved (2). Diethyl ether is the best solvent for dissolving the mixture, because though it is a polar molecule, its ethyl groups make it a nonpolar solvent. The compounds, fluorene and 1, 4-dibromobenzene, are also nonpolar; therefore, it would be easier for it to be dissolved in this organic solvent.
Zirconia has three crystalline forms: monoclinic phase, tetragonal phase and cubic phase. Monoclinic phase exists in zirconia stable up to temperature 1170˚C. Above 1170˚C, the monoclinic phase transforms to tetragonal phase and further transform to cubic phase above 2370˚C. While cooling down below 1070˚C, tetragonal phase becomes unstable and start transformation of monoclinic phase. Thus tetragonal phase is hard to exist at the room temperature.
More recently than Zeck’s work, Cesare et al. (1997), only divided the xenoliths into two main types: garnet-biotite-sillimanite and spinel-cordierite xenoliths. The quartz-cordierite rocks, distinguished by Zeck (1970), were interpreted as the products of interaction between garnet-biotite-sillimanite xenoliths and blebs of mafic magma and are not recognised. The xenoliths were observed to contain widespread occurrences of rhyolitic glass as...
The mass of Mg + the mass of O2=mass of MgxOx. Knowing the mass of
1. Obtain a clean, dry crucible and lid, then heat them for approximately 5 minutes over a Bunsen burner
Molybdenum is a transition metal. It is represented by the symbol Mo. It is a pure metal that is is silverish white in color and very hard, and has one of the highest melting points of all pure elements at 4753 °F. Its boiling point is 8382 °F. Its density is 10280 kg/m3 and its hardness is 5.5.
Paragraph 1: Compare and Contrast the crystal structures and crystal chemistry of Quartz α-FePO4 and β-FePO4. The research paper discusses the inversion of quartz type FePO4 from α-FePO4 to β-FePO4 along the temperature range 294K to 1073K. We first take a look at the difference in lattice and space symmetry between the 2 polymorphs, α-FePO4 and β-FePO4.
What is a crystal? Crystals are made up of elements which form amd there molecules form a certain pattern. For example, a volcano happens to erupts and magma flows out to the surface of the earth As the magma runs outward then slowly starts to cool. crystals may develop. This is call crystallization. From this occurring expensive crystal like rubies and diamonds are form, sometimes even emeralds. Crystals can have many different shape from the result of the type of molecules and atoms present in forming the crystals. Crystals can be put into thirty-two crystal classes then further put into a total of six systems..
with a tong to see if the magnesium had started to burn and also to
of Copper Sulphate. To do this I plan to work out the amount of water
• The use of a catalyst will speed up the reaction as long as the catalysts electrode potentials are feasible for each step in the reaction. Since a catalyst lowers the activation energy and takes the reaction through a different route, according to the Maxwell-Boltzmann diagram, at a constant temperature more particles are able to react as demonstrated by the diagrams below:
Scientists have long wanted to understand the environment and composition of the mantle. Teams of geologist have been trying for years to drill boreholes into the mantle. However, due to today’s technology and dwindling knowledge, as we get deeper and deeper into Earth, no one has come remotely close to getting there. Despite the failed attempts to collect material from the mantle, there are other ways that the mantle can be studied. One way is to study minerals that we can expect to find in the mantle such as wadsleyite. Wadsleyite was first discovered in the Peace River meteorite at Peace River, Alberta, Canada in 1966 and named after mineralogist Arthur David Wadsley. A phase transformation of the olivine, forsterite, wadsleyite is expected
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.
Rock sample B is gneiss. This sample was easy to identify based on the obvious banding throughout the layers of the sample. Gneiss is another metamorphic rock that originally was an igneous rock, granite. Through the process of metamorphism, the heat and pressures associated with the process may have caused the layers of mineral grains to flatten. “Gneiss displays distinct alternating layers composed of different minerals. Gneiss does not break along planes of foliation because less than 50% of the minerals formed during the metamorphism are aligned in thin layers” (UA, 2005). A visual inspection of the rock shows the quartz and feldspar composition within the layers of the sample.
The perovskite materials are of considerable technological importance, particularly with regard to physical properties such as pyro and piezoelectricity , dielectric susceptibility, linear and nonlinear optic effects. Many of these properties are gross effects, varying enormously from one perovskite to another and differences in crystal structures are hardly apparent . Effects of the impending transition are evident in some of the crystal properties at temperatures at least a few degrees away from Tc . Substances BaTiO3 and SrTiO3 have very high values of the permittivity due to low frequency of soft mode . It may be inferred that at room temperature BaTiO3 exhibits number of advantages over the other ferroelectrics such as a high mechanical strength , resistance to heat (due to positive temperature coefficient restivity , PTCR ) and moisture , presence of ferroelectric properties with in a broad range of temperature (its Curie point is high ≈ 400 K ) and ease of manufacturing . The presence of an abnormally high permittivity in BaTiO3 is connected with the ‘looseness’ of the crystal lattice of this substance . ( The sum of the atomic radii of titanium and oxygen ions 1.96 is less than the distance between these ions in the lattice 1.99 . The compression of the structure when atom of Ba is replaced by that of Sr drastically reduces dielectric constant and the temperature of the Curie point ) .