Thursday, September 26, 2019

Methods Used For Magnesium Essay Example | Topics and Well Written Essays - 5000 words

Methods Used For Magnesium - Essay Example Magnesium is an alkaline earth metal, belongs to the second group of s-block of the periodic table and is on the left side of the table. Magnesium is represented by â€Å"Mg† and has an atomic number of 12. The atomic weight of magnesium is 24.3050(6) and atomic volume of 14.0 cm3/mol. The electronic configuration is s2 2s2 2p6 3s2. Generally exhibits Hexagonal Close-packed lattice structure. The lattice dimensions of Magnesium at 25?C are Side length=0.32092 nm Height=0.52105 nm. At room temperature, actual c/a ratio reaches 1.6236 where magnesium becomes almost closely packed (Magnesium, 2000). It contains two electrons in the outer shell and being loses them in order to form a positive ion in the closed shell such as Mg+2. The energy level of magnesium is 3 as First energy level 2 Second energy level 8 Third energy level 2 Figure 1: Electronic configuration of magnesium Magnesium is silvery white or greyish, lightweight and strong metal. It is highly flammable metal and tar nished when in contact with air; therefore, it develops a thin layer of oxide. Magnesium is abundantly present in both earth crust and seawater due to its high solubility. However, magnesium is not present as free metal because of its reactive property (Gupta & Sharon, 2011). Magnesium has density of 1.738 at 20?C. The melting point of Mg is 650?C and its boiling point is 1107?C. It has a heat of fusion of 8.48 kJ ·mol?1 and its heat of vaporization is 128 kJ ·mol?1, whilst its molar heat capacity is 24.869 J ·mol?1 ·K?1. Magnesium is a strongly basic oxidant. Other atomic properties of Mg include its electronegativity of 1.31 (Pauling Scale), the atomic radius of 160 pm, and covalent radius of 141 ±7 pm (Magnesium Facts, 2012). Moreover, magnesium is paramagnetic is nature and its other mechanical properties include Young’s Modulus of 45GPa, Shear Modulus of 17GPa and Bulk Modulus of 45GPa. The hardness value of Magnesium is 260MPa based on Brinell Scale. Th e oxidation number of magnesium is +2 and is been found in a number of compounds. Magnesium Oxide, also called magnesia, is the second most abundant metallic oxide in the earth after Aluminium Oxide. Other forms of magnesium in the compound state include hydrated magnesium sulfate (MgSO4.7H2O), also called Epsom Salt. Magnesium compounds also include Magnesium Carbonate and Magnesium Fluoride (Willett, 2007). Dolomite, magnesite, brucite, carnallite, talc, and olivine are the main commercial sources of magnesium. Due to the presence of Mg+2 ions, seawater is considered another major source of magnesium. Magnesium hydroxide precipitates can be formed by adding calcium hydroxide in seawater for obtaining magnesium (Avedesian & Baker, 1999). MgCl2 + Ca(OH)2 > Mg(OH)2 + CaCl2 Brucite is insoluble in water and can be transformed into magnesium chloride when reacts with hydrochloric acid. Magnesium, then, can be extracted from magnesium chloride by the electrolysis process. Mg (OH)2 + 2 H Cl > MgCl2 + 2 H2O In electrolysis process, Mg+2 ion is transformed into magnesium metal by adding two electrons at the cathode while chlorine ions are oxidized to chlorine gas by releasing two electrons at the anode. Mg2+ + 2 e- > Mg (Cathode Reaction) 2 Cl? > Cl2 (g) + 2 e- (Anode Reaction) Magnesium has three isotopes (e.g. 24Mg, 25Mg and 26Mg) available in significant amounts with 24Mg comprising 79% of total magnesium. 28Mg is radioactive in nature; however, its usage in the nuclear industry has been limited due to its short life (21 hours).  

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