Magnesium single crystal 12Mg24.312
Magnesium was recognized as an element in 1755 by Joseph Black at Edinburgh, Scotland; isolated by Sir Humphry Davy in 1808.
[Greek, Magnesia = district of Thessaly]
French: magnésium
German: magnesium
Italian: magnesio
Spanish: magnesio
Description: Magnesium is a silvery-white, lustrous and relatively soft metal. It is obtained by the electrolysis of fused MgCl2. Magnesium burns in air when ignited and it reacts with hot water. It is used as the bulk metal and in leightweight alloys. Magnesium as a 'sacrificial' electrode will protect other metals that are exposed to seawater and groud water.
Magnesium single crystal properties
| State: |
single crystal |
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| Crystal structure: |
hexagonal |
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| Production method: |
Bridgman |
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| Standard size: |
diameter 10-20mm
thickness 1-2 |
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| Orientation: |
(0001), (1-100) and (11-20) |
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| Orientation accuracy: |
<2°, <1°, <0.4° or <0.1° |
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| Polishing: |
as cut, one or two sides polished |
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| Roughness of surface: |
<0.03µm |
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| Purity: |
99.999% |
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| Typical analysis (ppm): |
C 3
H < 1
O 9
N < 5
Cu 1.60
Fe 1.80
Ni < 1
Pb 0.30
Si 0.30
Ga, Hf and Ta are below the detection limit
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Materials properties
| Density: |
1.74 g/cm3 |
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| Melting point: |
648.85 °C / 922.0 °K |
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| Boiling point: |
1089.85 °C / 1363 °K |
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| Molar volume: |
13.98 cm3 |
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| Thermal conductivity: |
156 [300 K] Wm-1K-1 |
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| Coefficient of linear thermal expansion: |
26.1 x 10-6 K-1 |
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| Electrical resistivity: |
4.38x 10-8 [293 K] Wm |
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| Mass magnetic susceptibility: |
+6.8 x 10-9(s) kg-1m3 |
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| Young's modulus: |
44.7 GPa |
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| Rigidity modulus: |
17.3 GPa |
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| Bulk modulus: |
35.6 GPa |
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| Poisson's ratio: |
0.291 |
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| Radii: |
Mg2+ 79; atomic 160; covalent 136 |
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| Electronegativity: |
1.31 (Pauling); 1.23 (Allred); 3.75 eV (absolute) |
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| Effective nuclear charge: |
2.85 (Slater); 3.31 (Clementi); 4.15 (Froese-Fischer) |
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| Number of Isotopes (incl. nuclear isomers): |
12 |
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| Issotope mass range: |
20 -> 31 |
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| Crystal structure, (cell dimentions / pm), space group |
hexagonal |
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| X-ray diffraction: mass absorption coefficients: |
CuKα 38.6 (µ/r) / cm2g-1
MoKα 4.11 (µ/r) / cm2g-1 |
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| Neutron scattering length: |
0.5375 b/10-12 cm |
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| Thermal neutron capture cross-section: |
0.063 sa / barns |
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Biological data
| Biological role: |
Essential to all species |
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| Toxicity |
|
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| Toxic intake: |
low toxicity |
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| Lethal intake: |
LD50 (chloride, oral, rat)=8100 mg kg-1 |
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| Hazards: |
Magnesium compounds vary in toxicity but there is no evidence that magnesium itself produces systemic poisoning. |
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| Level in humans |
|
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| Blood: |
37.8 mg dm-3 |
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| Bone: |
700 - 1800 p.p.m. |
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| Liver: |
590 p.p.m. |
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| Muscle: |
900 p.p.m. |
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| Daily dietary intake: |
250 - 380 mg |
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| Total mass of element in average [70 kg] person: |
19 g |
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Geological data
| Mineral | Formula | Density | Hardness | Crystal apperance |
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| Brucite |
Mg(OH)2 |
2.39 |
2.5 |
rhom., waxy/vit. white |
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| Carnallite |
KMgCl3 |
1.602 |
2.5 |
orth., greasy, colourless reddish |
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| Cordierite |
Mg2Al4Si5O18 |
2.57 |
7 |
orth., translucent grey/lilac etc. |
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| Diopside |
CaMgSi2O6 |
3.3 |
5.5 - 6.5 |
mon., vit./resinous white/yellow |
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| Dolomite |
CaMg(CO3)2 |
2.85 |
3.4 - 4 |
rhom., vit. colourless |
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| Enstatite |
Mg2Si2O6 |
3.209 |
6 - 6 |
orth., pearly/vit., colourless grey |
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| Chief ore: |
seawater; and teh ores dolomite, magnestite; carnallite, kieserite and brucite |
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| World production: |
325000 tonnes/year |
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| Main mining areas: |
Austria, China, Poland, Russia, USA, India, Greece, Cananda |
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| Reserves: |
>2 x 1010 tonnes as ores ; and >1 x 1024 tonnes in the sea |
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| Specimen: |
available as chips, granules, powder, ribbon, rod or turnings. Safe. |
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| Abundances |
|
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| Sun: |
4.0 x 107 (relative to H = 1 x 1012) |
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| Earth's crust: |
23000 p.p.m. |
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| Seawater: |
|
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| Residence time: |
|
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| Classification: |
accumulating |
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| Oxidation state: |
II |
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Source: Emsley, J. (1998) The Elements (3rd Edition)
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