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Manganese 25Mn54.938
Isolated in 1774 by J.G. Gahn at Stockholm, Sweden.
[Latin: magnes = magnet or magnesia nigri = black magnesia (MnO2)]
French: manganèse
German: Mangan
Italian: manganese
Spanish: manganeso
Description: Manganese is a
hard, brittle, silvery metal. It is reactive when pure, burns in oxygen, reacts
with water and dissolves in dilute acids. It is used in steel production and to
make ceramics. Its compounds are used as feed supplements and fertilizer additives.
Materials properties
| Density: |
7440 (α) kg/m-3 [293 K]; 6430 [liquid at m.p.] |
| Melting point: |
1517 °K |
| Boiling point: |
2235 °K |
| Molar volume: |
7.38 cm3 |
| Thermal conductivity: |
7.82 [300 K] Wm-1K-1 |
| Coefficient of linear thermal expansion: |
22 x 10-6 K-1 |
| Electrical resistivity: |
185.0 x 10-8 [298 K] Wm |
| Mass magnetic susceptibility: |
+1.21 x 10-7(s) kg-1m3 |
| Young's modulus: |
191 GPa |
| Rigidity modulus: |
79.5 GPa |
| Bulk modulus: |
n.a. |
| Poisson's ratio: |
0.24 GPa |
| Radii: |
Mn4+ 52; Mn3+ 70; Mn2+91; atomic 124; covalent 117 |
| Electronegativity: |
1.55 (Pauling); 1.60 (Allred); 3.72 eV (absolute) |
| Effective nuclear charge: |
3.60 (Slater); 5.23 (Clementi); 7.17 (Froese-Fischer) |
| Number of Isotopes (incl. nuclear isomers): |
15 |
| Issotope mass range: |
49 -> 62 |
Biological data
| Biological role: |
Essential to all species. |
| Toxicity |
|
| Toxic intake: |
slightly toxic by ingestion. |
| Lethal intake: |
LD50(chloride, oral, mouse) = 1715 mg kg-1 |
| Hazards: |
Few poisonings have been caused by ingesting
manganese compounds, but exposure to dust or fumes is a health hazard and
working conditions should not exceed 5 mg m-1 even for short
periods. Its compounds are experimental carcinogens and teratogens.
|
| Level in humans |
|
| Blood: |
0.0016 - 0.075 mg dm-3 |
| Bone: |
0.2 - 100 p.p.m. |
| Liver: |
3.6 - 9.6 p.p.m. |
| Muscle: |
0.2 - 2.3 p.p.m. |
| Daily dietary intake : |
0.4 - 10 mg |
| Total mass of element in average [70 kg] person: |
12 mg |
Crystal data
| Crystal structure, (cell dimentions / pm), space group |
α-Mn b.c.c. (a = 891.39), I43m β-Mn b.c.c. (a=631.45), P4132 γ-Mn f.c.c. (a=386.3), Fm3m δ-Mn b.c.c. (a=308.1), Im3m T(α->β)= 973 K; T(β->γ) = 1352 K; T(γ->δ)= 1413 K |
| X-ray diffraction: mass absorption coefficients (µ/ρ) /cm2g-1: |
CuKα 285 MoKα 34.7 |
| Neutron scattering length, b/10-12cm: |
- 0.373 |
| Thermal neutron capture cross-section, σa/barns : |
13.3 |
Geological data
| Minerals: |
Many minerals are known. |
| Mineral |
Formula |
Density |
Hardness |
Crystal apperance |
| Bixbyite |
(Mn,Fe)2O3 |
4.975 |
6 - 6.5 |
cub. met. black |
| Manganite |
γ -MnO(OH) |
4.33 |
4 |
mon., met. grey-black |
| Pyrolusite |
β -MnO2 |
5.06 |
2 - 6 |
tet., met. grey-black |
| Rhodochrosite |
MnCO3 |
3.4 - 3.6 |
3.5 - 4 |
rhom., vit. pink |
| Rhodonite* |
(Mn,Fe,Mg)SiO3 |
3.6 |
5.5 - 6.5 |
tric., vit. rose-pink |
| Romanechite |
BaMn9O16(OH)4 |
3.7 - 4.7 |
5 - 6 |
mon., met.black,fern-like |
*Used in jewelry.
| Chief ore: |
pyrolusite, romanechite (also known as psilomelane), manganite (useful but rare) |
| World production: |
6.22 x 106 tonnes/year |
| Main mining areas: |
South Africa, Russia, Gabon, Australia, Brazil |
| Reserves: |
3.6 x 109 tonnes (plus ocean floor nodules which are 24% Mn) |
| Specimen: |
available as chips, flake or powder. Safe. |
| Abundances |
|
| Sun: |
2.63 x 105 (relative to H = 1 x 1023) |
| Earth's crust: |
950 p.p.m. |
| Seawater: |
|
| Atlantic surface: |
1.0 x 10-4 p.p.m. |
| Atlantic deep: |
0.96 x 10-4 p.p.m. |
| Pacific surface: |
1.0 x 10-4 p.p.m. |
| Pacific deep: |
0.4 x 10-4 p.p.m. |
| Residence time: |
50 years |
| Classification: |
scavenged |
| Oxidation state: |
II |
Other sizes and specifications on request
© 1996 - 2008 MaTecK GmbH - Im Langenbroich 20 - D-52428 Juelich - phone: +49 (0) 2461 / 9352-0 - fax: +49 (0) 2461 / 9352-11 - Contact: info@mateck.de
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