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Minerals in Detail
Chemical Details | Description | Industrial Applications |
In Nature | Health Impacts | Daily Intake
MANGANESE
Manganese - chemical details
| Symbol | Mn |
| Atomic number | 25 |
| Atomic mass | 54.9380 g.mol-1 |
| Electronegativity | 1.5 (according to Pauling) |
| Density | 7.43 g.cm-3 at 20°C |
| Melting point | 1247 °C |
| Boiling point | 2061 °C |
| Vanderwaals radius | 0.126 nm |
| Ionic radius | 0.08 nm (+2) |
| 0.046 nm (+7) |
| Isotopes | 7 |
| Electronic configuration | [ Ar ] 3d5 4s2 |
| Energy of first ionisation | 716 kJ.mol-1 |
| Energy of second ionisation | 1489 kJ.mol-1 |
| Standard potential | - 1.05 V ( Mn2+/ Mn ) |
| Discovered | 1774 - Johann Gahn |
Chemical Details | Description | Industrial Applications |
In Nature | Health Impacts | Daily Intake
Manganese - Description
Manganese is a pinkish-grey, chemically active element. It is a hard metal and is very brittle. It is difficult to melt, but easily oxidised. Manganese is
reactive when pure, and as a powder it will burn in oxygen. It reacts with water (it rusts like iron) and dissolves in dilute acids.
Chemical Details | Description | Industrial Applications |
In Nature | Health Impacts | Daily Intake
Manganese - Industrial applications
Manganese is widely used in the manufacture of steel, glass, disinfectants, fertilisers and ceramics. For details on
industrial applications and impact on the environment see www.lenntech.com/Periodic-chart-elements/Mn-en.htm
Chemical Details | Description | Industrial Applications |
In Nature | Health Impacts | Daily Intake
Manganese - In natural form
Manganese is one of the most abundant metals in soils, where it occurs as oxides and hydroxides, and it cycles through its various oxidation states.
Manganese occurs principally as pyrolusite (MnO2), and to a lesser extent as rhodochrosite (MnCO3). More than 25 million tonnes are mined every year,
and reserves are estimated to exceed 3 billion tonnes. The main mining areas for manganese ores are South Africa, Russia, Ukraine, Georgia, Gabon and
Australia.
Manganese is an essential element for all species. Some organisms, such as diatoms, molluscs and sponges, accumulate manganese. Fish can have up to 5 ppm
and mammals up to 3 ppm in their tissue, although normally they have around 1 ppm.
Chemical Details | Description | Industrial Applications |
In Nature | Health Impacts | Daily Intake
Manganese - Impact on health
Manganese is one of three toxic essential trace elements, which means that it is not only necessary for humans to survive, but it is also toxic when too
much is present in the human body.
Manganese is a component of some enzymes and stimulates the development and activity of other enzymes. Manganese
superoxide dismutase (MnSOD) is the principal antioxidant in mitochondria. Several enzymes activated by manganese contribute to the metabolism of
carbohydrates, amino acids, and cholesterol.The classes of enzymes that have manganese cofactors are very broad and include such classes as oxidoreductases,
transferases, hydrolases, lyases, isomerases, ligases, lectins, and integrins.
The uptake of manganese by humans mainly takes place through food, such as spinach, tea and herbs. The foodstuffs that contain the highest concentrations
are grains and rice, soya beans, eggs, nuts, olive oil, green beans and oysters. Note that the nutritious kernel (wheat germ) of most processed grains
(white bread), which contains the most minerals and vitamins of the grain, has been removed because it is dark and "impure". After absorption in the human
body manganese will be transported through the blood to the liver, the kidneys, the pancreas and the endocrine glands.
Symptoms of manganese poisoning are hallucinations, forgetfulness and nerve damage. Manganese effects occur mainly in the respiratory tract and in the
brains. A syndrome that is caused by manganese has symptoms such as schizophrenia, dullness, weak muscles, headaches and insomnia.
Because manganese is an essential element for human health, shortages of manganese can have the following effects:
Birth defects
Blood clotting
Cholesterol (levels too low)
Glucose intolerance
Changes of hair colour
Neurological symptoms
Obesity
Skin problems
Skeleton disorders
Chemical Details | Description | Industrial Applications |
In Nature | Health Impacts | Daily Intake
Manganese - Recommended daily & maximum intake
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Risk free |
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intake? |
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Food sources? |
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Result of overdose? |
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RDA |
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Limit |
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Infants
0-6 mo
7-12 mo
Children
1-3 y
4-8 y
Males
9-13 y
14-18 y
19-30 y
31-50 y
50-70 y
> 70 y
Females
9-13 y
14-18 y
19-30 y
31-50 y
50-70 y
> 70 y
Pregnancy
< 19 y
19-30 y
31+ y
Lactation
< 19 y
19-30 y
31+ y |
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(mg/d)
0.003
0.600
1.2
1.5
1.9
2.2
2.3
2.3
2.3
2.3
1.6
1.6
1.8
1.8
1.8
1.8
2.0
2.0
2.0
2.6
2.6
2.6 |
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(mg/d)
ND
ND
2.0
3.0
6.0
9.0
11.0
11.0
11.0
11.0
6.0
9.0
11.0
11.0
11.0
11.0
9.0
11.0
11.0
9.0
11.0
11.0 |
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Legumes
Nuts
Whole grains |
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Elevated blood concentration
Neurotoxicity (poisoning of the nervous system) |
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Explanations:
ND = Not determinable. There is either insufficient data on adverse effects and/or concern with the body's ability to handle excess amounts. In most
instances it is wise not to supplement for this particular element, but to rely on diet to provide sufficient quantities.
RDA = Recommended Dietary Allowance. May be used as a goal for daily intake. RDAs are set at a level that should meet the needs of 97-98% of all individuals.1, 2, 3, 4
Limit = The maximum level of daily nutrient intake from all sources that is highly likely to pose no risk of adverse effects.1, 2, 3, 4
References:
- Standing Committee on the Scientific Evaluation of Dietary Reference Intakes (1997). Dietary Reference Intakes for Calcium, Phosphorous, Magnesium, Vitamin D, and Fluoride. Food and Nutrition Board: Institute of Medicine.
- Standing Committee on the Scientific Evaluation of Dietary Reference Intakes (1998). Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6,
Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Food and Nutrition Board: Institute of Medicine.
- Standing Committee on the Scientific Evaluation of Dietary Reference Intakes (2000). Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. Food and Nutrition Board: Institute of Medicine.
- Standing Committee on the Scientific Evaluation of Dietary Reference Intakes (2001). Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Food and Nutrition Board: Institute of Medicine.
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