Fe Oxide Experiment-Solid State Chemistry, X-ray Diffraction and Characterisation of Fe Oxides - Essay Example

? Fe Oxide Experiment-Solid Chemistry, X-ray Diffraction and Characterisation of Fe Oxides Introduction X-ray diffraction is critical in elemental and compound analysis in numerous fields of chemistry and their related applications. Throughout this experiment, there will be studying more of the X-ray diffraction techniques and the characterization of materials made in the previous experiments such as Fe3O4 and ?-Fe2O3. Basically, there will be exploration of the use of the X-ray diffraction as an analytical technique for the characterization of material. The essence of characterizing solid materials is to realize the specific categories of grouping the solid substances according to their components and functionality. Considering substances such as the NaCl, the technique would assist in its analysis and the realization of its application in daily life such as table salt. Diffraction is the phenomenon through which interference amid waves and normally occurs as a result of underlying object being within their path. X-ray diffractometer normally carry out both qualitative accompanied quantitative analysis of the underlying polycrystalline materials. The MiniFlex is normally in dual variations namely the functioning at 600 watts within the x-ray tube; the MiniFlex 600 is normally double as dominant as the other bench top models, which enable faster analysis and the corresponding advanced overall throughout. The second running at 300 watts with the x-tube, the recent MiniFlex 300 does not demand a peripheral heat exchanger. The incident beam of underlying waves approaches the object accompanied by the object which causes the prevailing alteration within the path of the waves. The impacts are mostly realized where the wavelength of the incident is about the same as the corresponding proportions of the diffracting objects (Cornell & Schwertmann 2003). X-rays are normally section of the electromagnetic spectrum and consist of wavelength ranging amid 0.01nm to 10nm. The distance amid the wavelength is the same similar distance of atoms within a solid thus utilize in predicting the arrangement of the atoms within a solid. There is always alteration of direction when the underlying incident X-ray hits a solid material (Villars, , Cenzual & Penzo 2012). Pre-lab questions 1. Write a brief account of the different iron oxides, detailing their formulae, solid state structures and magnetic properties. What industrial uses do the oxides have? FeO This is Iron (ii) Oxide with a chemical formula as stated above and is a black powder. The compound consists of iron element composing of iron as an element in oxidation form of two bonded to oxygen. http://www.webelements.com/_media/compounds/Fe/Fe1O1-1345251.jpg Iron ii oxide magnetic NPs possess numerous peculiar magnetic properties that mainly entail super paramagnetic, high coercively, low Curie temperature, high magnetic, and susceptibility. These magnetic NPs are normally utilized within the significant bioapplications, including magnetic bioseparation and recognition of biological entities that include cell, protein, nucleic acids, enzyme, bacterial, and virus, clinic analysis accompanied by therapy magnetic resonance image and the corresponding magnetic fluid hyperthermia, tar. This occasionally targets drug delivery and biological labels. Moreover, magnetic iron oxide NPs became the strong candidates, and the corresponding application of small iron oxide NPs within the vitro diagnostics Fe3O4 Magnetite is an ordinary iron oxide magnet hence making it to possess extremely distinguishing feature. Magnetite is the mainly magnetic of entire the minerals on Earth. Fe3O4 exist within the laboratory as a black powder and exhibits permanent magnetism and corresponding ferromagnetic. It is most extensive utilize as a black pigment which is synthesised relatively to being extracted from the existing naturally occurring mineral as the atom size and shape. This is normally varied through the underlying method of production http://t1.gstatic.com/images?q=tbn:ANd9GcSTXAHa0CC8NcmzPj98NG4dBtu1oNiyi9ASm61LNrMuQdxl3RKG4A ?-Fe2O3 ?-Fe2O3 is mostly attained through conventional method for either Fe3O4 or c-Fe2O3 by the co-precipitation. The method mainly entail mixing ferric and corresponding ferrous ions in the 1:2 molar ratio within highly basic solutions at room temperature or at elevated temperature. The size and shape of the iron oxide NPs depends on the type of salt employed, the ferric and ferrous ions ratio, the existing reaction temperature, the PH value, ionic strength of the prevailing media, and the other supplementary reaction parameters. ?-Fe2O3 possess most stable and corresponding ideal morphological and magnetic properties. The prevailing idea of producing an expandable magnetic polymer through mixing super paramagnetic iron oxide particles and silicone sealant 2. FeO has the rock salt structure – draw a draw a plan and clinographic view to illustrate the arrangement of ions FeO which has the rock salt structure. Calculate the number of each ion in the unit cell and verify the stoichiometry http://eurjmin.geoscienceworld.org/content/18/1/113/F5.expansion.html Calculations 8 particles on the lattice corners = 8 x 1/8 = 1 particle 6 particles that have half of their volumes in the lattice volume = 6 particles x 1/2 = 3 particles. Total = 1 + 3 = 4 Question 3 FeO, Fe3O4 and ?-Fe2O3 are all based on an oxide FCC lattice. Explain: This is because; all these compounds are based on the Face- Centered – Cubic lattice. They have the same cubic closely arranged array of oxide ions. a) What is meant by “an FCC lattice” FCC lattice is an arrangement pattern of atoms called Face- Centered – Cubic unit cell. A unit cell is composed of atoms located at fixed positions determined by imaginary line known as lattice. There are atoms at every corner of the cube face. Compounds with this type of lattice incorporate the ?-Fe2O3 and other ductile materials. The gamma iron has its atoms arranged in the fcc format and are non magnetic in nature. FCC has lattice locations on the faces of each cube, that every face provides precisely a half donation hence, giving a total of 4 lattice points per unit cell. The two layer expression of fcc illustrates that there are six molecules with 50% of their quantities within the lattice. The calculation of the particles is as shown. http://www.chem.wisc.edu/areas/CLC/general/103/crystalLattices/layer2.gif http://www.chem.wisc.edu/areas/CLC/general/103/crystalLattices/formula2.gif b) Why do you think it is easy to convert between Fe, FeO, Fe3O4 and ?-Fe2O3 through the application of heat? These compounds have close Curie temperatures at which their magnetic properties change permanently and have the slightest phase of transition of about 120K and at which the structure is altered through discontinuing the structure. Methods: X-Ray Diffraction X-rays have shorter wavelengths and it is this property that makes them capable of determining the shortest distances as the intra atomic distances. The rays scattered between dissimilar objects especially the atoms in this case impede with each other. In case the rays are out of step they would eliminate one another. In case the rays are in step they would attain reinforcement from each other. In this case the samples are put in the chamber and the machine turned on. The results are then displayed in radiographs. http://www.leeds.ac.uk/heritage/Astbury/X_ray_diffraction/x_ray_diffraction.jpg Experiment 1 The steps involved weighing about 0.5 g of iron (II) oxalate and put into 100ml beaker. A homogeneous spreading of the iron oxalate was ensured at the base of the beaker. The beaker was put on a hot plate and the temperature control setting was then turned to the maximum for highest temperature. The maximum heat was applied for ca ten minutes until the iron oxalate solid in the beaker turned its colour from yellow to dark brown. However during the heating, the beaker should be shaken from time to time. A precaution was taken where the beaker was handled with heat proof gloves to avoid burns because it was very hot. After every shake, the uniform spread of the solid at the base of the beaker was ensured for uniform distribution of heat and the formation of lumps. At the end of the heating exercise, lumps of solid that had initially formed were broken down using a spatula and checked if both inside as well as the outside had turned brown equally. In case inside was still yellow in colour the solid was heated to attain a brown colour. After the solid had all become dark brown in colour, the solid was put on a ceramic tile and left to cool to attain the room temperature. In this case, the caution taken was similar to the previous because the beaker was still very hot. Once the sample was cooled, it was placed into a sample vial after which its weight was recorded. The vial was them marked after which calculations of the yield was made (RAO & Joshi, 1995). Experiment 2 This experiment entailed the preparation of Fe3O4 by heating the iron (II) oxalate under a nitrogen environment. The process involved taking ca 0.2 g of iron oxalate (but was made to 1.0g) and placed into a 3-necked 100 mL round bottomed flask. The flask was then clamped to a retort stand. A nitrogen outlet adaptor was attached to one of the outer necks and ensured to be connected to one of the blue nitrogen taps. A ground glass bung was placed in the middle neck. A nitrogen bubbler had to be attached to the third neck. It was ensured that “U”-bend in the bubbler contained a given amount of oil and any taps linked to it closed. Then the nitrogen tap was turned on. A precaution was taken to ensure that the flow was gentle and the number of bubbles produced per second by the bubble could be counted. A perfect flow of about 5-6 drops per second was ensured. The nitrogen was flushed for five minutes by letting the nitrogen to run through it (Brundle 1992). The apparatus was then checked and approved by the technical staff. The solid was heated in the flask using the highest non luminous flame setting of the Bunsen burner. The yellow solid turned to black after being heated for few minutes. The flask was shaken during the heating to make sure that the entire solid got heated and the uniformity in heating maintained. However, the plastic tubing attached to the flask was prevented from heat to evade melting. When the solid all turned to black, the Bunsen burner was put out and the flask was left to cool in order to attain the room temperature without turning the nitrogen flow since it is crucial to allow the nitrogen to continue flowing throughout this time. The precaution maintained for taking this measure was to prepare the rightful iron oxide. Once the flask cooled, the nitrogen flow was turned off; the fittings were removed from the round bottomed flask before the solid was eventually transferred to a clean and noted vial. The mass of the solid produced as well as the yield was then determined (Gajbhiye, & Date 2009). Towards the conclusion? ?-Fe2O3 was made half of the Fe3O4 Prepared in the experiment 2 was collected into a 100ml beaker, while proper recording was undertaken. The vital quantities of the reagents are critically recorded down. A spatula was used in the spreading of the iron oxide finely on the base bottom of the beaker. The beaker was then placed on a hot plate and the control for the temperature set up to maximum unit. The heat was provided to the beaker for up to ten minutes, finally the solid turned dark brown colour. The beaker was repeatedly shaken in the process of heating; however, at this point, it was a cautious process not incurs injuries from the hotness of the beaker. At the end of each shaking, we ensured that the solids were evenly distributed on base of the beaker. In the process towards the end of the experiment large lumps of the solids were broken to smaller particles to check if both inside and the outsides were brown. In the presence of black inside of the lumps then the solids were reheated. Experiment 3 Eventually, ?-Fe2O3 was made. One half of Fe3O4 made in experiment 2 was taken and transferred to 100ml beaker and the exact quantities used in the lab book remembered. Spatula was used to spread the iron oxide throughout the base of the beaker uniformly. The beaker was placed on a hot plate and the temperature regulator turned on to its maximum heat setting. The heat was applied for about 10 minutes till the solid had changed to dark brown in colour. The shaking of beaker was maintained from time to time while taking the precaution that the beaker was very hot and handled with heat proof gloves. The maintained solid was evenly spread at the base of the beaker even after shaking. Headed for the end of experiment, lamps of solid were broken up using the spatula and booth the inside and outside of the lumps checked if brown. In case the inside of the lamp was still black, it was heated for longer till it became brown (Singh & Gra?Fe 2010). After all the solids were brown then it was turned in to a ceramic tile and left to cool to the room temperature. After the cooling, the solid is placed into a sample vial. The vial was then labelled and the weight recorded until the following week when the yield of reaction was calculated. At the closure of all the process the vials were labelled and given to member for future purposes (Balasubramaniam 2005). The solid was placed on a ceramic tile when it had all gone to dark brown and left to cool to room temperature. The sample was then placed into a sample vial once it was cool and the weight was recorded. The vial was labelled well since it would be needed for future experiments. Results The positioning of the Hydrogen atoms normally makes very mere contributions and thus X-ray crystallography is not appropriate for accurately positioning the hydrogen atoms (Villars, Cenzual & Penzo 2012). In case the location of hydrogen atoms is of a particular interest then the study of the existing hydride structures accompanied by the hydrogen bonding connections that utilizes the less existing method of the neutron diffraction in determining their locations. The corresponding theory of neutron diffraction is normally extremely same as the X-ray diffraction but an essential dissimilarity is that the hydrogen atoms disperse neutrons as efficiently as many as atoms and for the purpose that they can be positioned with the exactness within the structure fortitude (Somiya 1994). There is need for single crystals that is very fundamental in the determination of the detailed structure of the X-ray structure. Numerous compounds cannot be crystallised and therefore are not amenable to the underlying diffraction studies. Moreover, they are normally utilized in commercially significant materials that mainly entail glasses accompanied by several ceramics which be obliged their exclusive properties to their shapeless nature. Their amorphous structure makes them cumbersome to be examined in detail through diffraction techniques (Waseda & Suzuki 2006). For the underlying an orthogonal system (a = b = g = 90°) the association amid the prevailing interplanar spacing (d) accompanied by the corresponding unit cell parameters is normally displayed through the expression and solely apply for orthorhombic crystal (Miglierini 1999). For the tetragonal system it diminish to For the corresponding cubic system, it normally auxiliary reduces to The existing low temperature structure strength of mind when the corresponding X-ray data are gathered at lower temperature ( Read More