Magnesium

Name:Magnesium
Symbol:Mg
Atomic Number:12
Atomic Mass:24.3050
Density: 14.00 g/cm^3
Melting Point:650 °C
Boiling Point:1090 °C
Group Number:2
Group Name:Alkaline Earth Metals
Standard State:solid at room temperature
Color:silvery white
Classification:Metallic
Availability:magnesium is available in several forms including chips, granules, powder, rod, foil, sheet, rod, turnings, and ribbon.
Magnesium is a grayish-white, fairly tough metal.

Magnesium is the eighth most abundant element in the earth's crust although not found in it's elemental form. It is a Group 2 element.Group 2 elements are called alkaline earth metals.
Magnesium tarnishes slightly in air, and finely divided magnesium readily ignites upon heating in air and burns with a dazzling white flame. Normally magnesium is coated with a layer of oxide, MgO, that protects magnesium from air and water.
Magnesium metal burns with a very bright light. The picture above shows the color arising from adding magnesium powder to a burning mixture of potassium chlorate and sucrose. Do not attempt this reaction unless are a professionally qualified chemist and you have carried out a legally satisfactory hazard assessment.
Magnesium is an important element for plant and animal life. Chlorophylls are porphyrins based upon magnesium. The adult human daily requirement of magnesium is about 0.3 g day^-1.

Isolation

Magnesium can be made commercially by several processes and would not normally be made in the laboratory because of its ready availability. There are massive amounts of magnesium in seawater. This can be recovered as magnesium chloride, MgCl₂ through reaction with calcium oxide, CaO.

CaO + H₂O → Ca²⁺ + 2OH^-

Mg²⁺ + 2OH^- → Mg(OH)₂

Mg(OH)₂ + 2HCl → MgCl₂ + 2H₂O

Electrolysis of hot molten MgCl₂ affords magnesium as a liquid whih is poured off and chlorine gas.

cathode: Mg²⁺(l) + 2e^- → Mg anode: Cl^-(l) → ¹/₂Cl₂ (g) + e^-

The other methos used to produce magnesium is non electrolytic and involves dolomite, [MgCa(CO₃)₂], an important magnesium mineral. This is "calcined" by heating to form calcined dolomite, MgO.CaO, and this reacted with ferrosilicon alloy.

2[MgO*CaO] + FeSi → 2Mg + Ca₂SiO₄ + Fe

The magnesium may be distilled out from this mixture of products.