Manganese

characteristics
chrome - manganese - iron
Mn
Tc

[acre] 3d 5 4s 2
55
25
Mn

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generally
name, symbol, ordinal number manganese, Mn, 25
series of transition metals
Group, period, block 7, 4, D
appearance silvery metallically
atomically
atomic mass 54.938049
atomic radius (computed) 140 (161) pm
Kovalenter radius 139 pm
van the Waals radius -
Elektronenkonfiguration [acre] 3d 5 4s 2
electrons per energy level 2,8, 13, 2
electron affinity 4.1 eV
1. Ionization energy 717.3 kJ/mol
2. Ionization energy 1509 kJ/mol
3. Ionization energy 3248 kJ/mol
4. Ionization energy 4940 kJ/mol
5. Ionization energy 6990 kJ/mol
6. Ionization energy 9220 kJ/mol
7. Ionization energy 11500 kJ/mol
physically
state of aggregation (magnetism) firmly (usually
non-magnetic
)
crystal structure cubically body-centered
density (Mohshärte) 7470 kg/m 3 (6,0)
melting point 1517 K (1244 ° C)
boiling point 2235 K (1962 °C)
molecular volume 7,35 · 10 -6 m 3 /mol
heat of vaporization 226 kJ/mol
Heat of fusion 12.05 kJ/mol
steam pressure 121 Pa at 1517 K
speed of sound 5150 m/s with 293,15 K
specific thermal capacity 480 j (kg · K)
Electrical conductivity 0,695 · 10 6 S /m
heat conductivity 7.82 w (m · K)
Chemically
oxidation conditions 2, 3, 4,6, 7
oxides (basicity) (strongly sourly)
Elektronegativität 1.55 (Pauling scale)
isotopes
isotope NH t 1/2 ZM CPU M eV ZP
52 Mn {syn.} 5.591 D ε 4.712 52 CR
53 Mn {syn.} 3,74 · 10 6 A ε 0.597 53 CR
54 Mn {syn.} 312.3 D ε
β -
1.377
0.697
54 CR
54 Fe
55 Mn 100% Mn 56 Mn are stable {
syn. with 30 neutrons} 2.5785 h β - 3.695 56 Fe
NMR characteristics
55 Mn
nuclear spin 5/2
gamma/ wheel/T 6,598 · 10 7
sensitivity 0.175
Larmorfrequenz with B = 4.7 T 49.3 M cycles per second
as far as possible and common, is used SI-UNITs.
If not differently notes,
the indicated data apply Standard conditions.

Manganese (of franz. manganèse = black magnesia) is a chemical element in the periodic system of the elements with the symbol Mn and the ordinal number 25.

Table of contents

history

manganese connections is used for thousands of years by humans. Colors with manganese pigments from manganese dioxide can be retraced 17000 years. Romans and Egyptians used manganese connections in the glass production to the colouring andDecolorization. Spartaner used manganiferous iron ore for the production of their weapons. The fact that the high quality of the weapons was based on an iron manganese alloy must be regarded as speculation.

In 17. Century manufactured the chemist Johann Rudolph Glauber Permanganat. Center 18. Century usedone manganous oxide for the production of chlorine. On suggestion of the Swedish chemist Carl William cross-eyed one, who discovered 1774 that pyrolusite is not an iron ore, but an up to then unknown metal must contain, succeeded it of Johan God-dear yawns still in the same year,for the first time to make elementary manganese of pyrolusite by reduction with coal. Beginning 19. Century began the employment from manganese to the iron production. 1816 were well-known the firmness-increasing effect without increased brittleness.

occurrence

world-wide gives it very large manganese occurrences.At the structure of the earth's crust it is involved with approximately 900 ppm and is thereby after the iron the secondarymost frequent heavy metal. Well-known manganese ore occurrences worthy of exploitation are in

  • South Africa (Hotazel)
  • Georgien (Tschiatura)
  • Russia
  • Ukraine
  • Australia (Groote Eylandt)
  • Brazil
  • Gabon
  • India
  • People's Republic of China
  • Mexico
  • Burkina Faso
  • Ghana
  • Morocco

larger one quantities manganese the manganese nodules contain of the deep sea.

Germany is manganese ores, considerable quantities is e.g. poor in. in winner countries the Spateisensteinbezirk and in the middle Thüringer forest close Ilmenau.

Naturally occurring minerals:

  • Pyrolosit MNO2, one of the five modifications of the manganese dioxide
  • brewing rivet Mn 2 O 3, Manganit Mn 2 O 3 · H 2 0
  • Hausmanit Mn 3 O 4
  • Manganspat (Rhodochrosit) MnCO 3
  • Rhodonit MnSiO 3
  • Psilomelan (the “blackGlass head "), a well, a k and a Ba haltiges amorphous manganese dioxide

production and representation

manganese has a high affinity for the oxygen. Manganese ores cannot be reduced therefore just like Chromerze by coal to the element. As far as possible ferro-manganese becomes asManganese raw material assigned.

Metallic manganese is manufactured predominantly by electrolysis by manganese (II) - sulfate solutions:

<math> \ mathrm {2 MnSO_4 + 2 H_2O \ rightarrow 2 Mn + 2 H_2SO_4 + O_2}< /math>

Further, but rarely used manufacture ways are alumino and silicothermische reduction.

characteristics

Mangan
manganese

Manganese is resembling a grey-white, hard and very brittle heavy metal, in some characteristics the iron. Other sources prove absolutely carbon-free manganese than duktil .

Manganese seems mainly in the Oxidationsstufen to +2, +4 and +7. However all existOxidationsstufen from -3 to +7, whereby the manganese is the element with most different Oxidationsstufen. For reaching some of the oxidation numbers one needs however drastic conditions. Chemically Mn 2+ behaves often similarly the approx. 2+ and can this alsoin biological systems, e.g. replace in the bone. Mn +7 in form of the Permanganats is a frequently used and strong oxidizing agent. Elementary manganese is relatively inconsistant. It is attacked by water under hydrogen development. In diluted, not-oxidizing acids it separateslikewise. In the warmth it reacts with boron, carbon, silicon, nitrogen, phosphorus, oxygen, sulfur and the halogens. With hydrogen manganese does not react under formation of a hydride.

At air manganese is by educationan oxide film (protective layer) steadily.

proof

manganese ii-cations become for the proof reaction in the cation separation course in the so-called „alkaline bath “- a mixture out konz. Hydrogen peroxide and sodium hydroxide - to the manganese iv-cation oxidizes. The manganese iv-oxide hydroxide „pyrolusite “becomes then by cooking in konz. Nitric acid solved and with lead iv-oxide to the violet Permanganat oxidizes:

1) Aufoxidation to the manganese iv-cation in the alkaline bath:

H 2 O 2 + Mn 2+ + 2 OH - MNO (OH) 2 (precipitation brown) + H 2 O

2) proof as Permanganatwith lead iv-oxide (or similarly by oxidation melt with soda and Salpeter):

Mn 4+ + 3 PbO 2 + 2 H 2 O → 2 MNO 4 - (pink-violet) + 3 Pb 2+ + 4 H +

also the Boraxperle becomesqualitative proof of some metals with the cation separation course in analytic chemistry uses. In presence of manganese ions it colors itself violet in the oxidation zone.

use

manganese is because of its high affinity for sulfur and oxygen as well as its material-improving characteristicsof high importance for the metallurgy. Approx. 90% to 95% of the produced manganese and/or ferro-manganese go into the iron, stealing and the special material production:

manganese dioxide serves as oxidizing agent in dry batteries.

The need of manganese becomes in the nextYears do not sink, since no economically meaningful spare technologies admits are.

physiology

bound manganese is an essential trace element for all ways of life. It activates enzymes and increases the utilization Vitamin of the B1, importantly is it for insulin production that Pancreas.

The human body contains about 300 ppm manganese, most of it is in the bones. Daily approximately 4 mg should be taken up. Manganese realm are Nüsse, full grain products, Keimlinge, strawberries and cocoa. Milk, mineral water and someDrinking water are manganese-poor.

safety references

manganese is relatively unproblematic compared with many other heavy metals. The danger of most connections is small and it became known practically never cases of poisoning by oral admission of manganese connections. Chronic manganese admission overthe respiratory system as dust is however toxic and leads to manganesism. This illness struck above all mountain workers, in addition, coworkers of battery factories and points themselves particularly by motor disturbances similarly the disease Parkinson by enrichment of the manganese to thatBasal ganglia. Contrary to the disease Parkinson is however resistant in relation to the conventional therapy forms (Levodopa) the manganesism. The contact with Permanganat can lead to Verätzungen.

connections

  • potassium permanganate one uses as strong oxidizing agent in the laboratory range. It becomes alsowhen tropical medicine uses, for example with the treatment of fish poisonings.
  • Manganese dioxide used as oxidizing agents in Trockenzellen (batteries of the type zinc coal, alkali manganese and lithium). As Glasmacherseife it is used for the decolorization of eisenhaltigen Glasschmelzen. It compensates the yellowColor of the Fe 3+ ions by a violet colouring.
  • Ferro-manganese as alloy addition in the metallurgical industry.
  • Himbeerspat (Rhodochrosit, manganese carbonate) pink to blood-red mineral for the production of gem stones.

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