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Name, Symbol, Number | Manganese, Mn, 25 | ||||||||||||||||||||||||||||||||||||
Chemical series | Transition metals | ||||||||||||||||||||||||||||||||||||
Group, Period, Block | 7 [?], 4 , d | ||||||||||||||||||||||||||||||||||||
Density, Hardness | 7470 kg/m3, 6.0 | ||||||||||||||||||||||||||||||||||||
Appearance | silvery metallic | ||||||||||||||||||||||||||||||||||||
Atomic Properties | |||||||||||||||||||||||||||||||||||||
Atomic weight | 54.938049 amu | ||||||||||||||||||||||||||||||||||||
Atomic radius (calc.) | 140 (161) pm | ||||||||||||||||||||||||||||||||||||
Covalent radius | 139 pm | ||||||||||||||||||||||||||||||||||||
van der Waals radius | n/a pm | ||||||||||||||||||||||||||||||||||||
Electron configuration | [Ar]3d54s2 | ||||||||||||||||||||||||||||||||||||
e- 's per energy level | 2, 8,13,2 | ||||||||||||||||||||||||||||||||||||
Oxidation states (Oxide) | 7,6,4,2,3 (strong acid) | ||||||||||||||||||||||||||||||||||||
Crystal structure | Cubic body centered | ||||||||||||||||||||||||||||||||||||
Physical Properties | |||||||||||||||||||||||||||||||||||||
State of matter | solid (usually nonmagnetic) | ||||||||||||||||||||||||||||||||||||
Melting point | 1517 K (2271 °F) | ||||||||||||||||||||||||||||||||||||
Boiling point | 2235 K (3564 °F) | ||||||||||||||||||||||||||||||||||||
Molar volume | 7.35 ×10-3 m3/mol | ||||||||||||||||||||||||||||||||||||
Heat of vaporization | 226 kJ/mol | ||||||||||||||||||||||||||||||||||||
Heat of fusion | 12.05 kJ/mol | ||||||||||||||||||||||||||||||||||||
Vapor pressure | 121 Pa at 1517 K | ||||||||||||||||||||||||||||||||||||
Velocity of sound | 5150 m/s at 293.15 K | ||||||||||||||||||||||||||||||||||||
Miscellaneous | |||||||||||||||||||||||||||||||||||||
Electronegativity | 1.55 (Pauling scale) | ||||||||||||||||||||||||||||||||||||
Specific heat capacity | 480 J/(kg*K) | ||||||||||||||||||||||||||||||||||||
Electrical conductivity | 0.695 106/m ohm | ||||||||||||||||||||||||||||||||||||
Thermal conductivity | 7.82 W/(m*K) | ||||||||||||||||||||||||||||||||||||
1st ionization potential | 717.3 kJ/mol | ||||||||||||||||||||||||||||||||||||
2nd ionization potential | 1509 kJ/mol | ||||||||||||||||||||||||||||||||||||
3rd ionization potential | 3248 kJ/mol | ||||||||||||||||||||||||||||||||||||
4th ionization potential | 4940 kJ/mol | ||||||||||||||||||||||||||||||||||||
5th ionization potential | 6990 kJ/mol | ||||||||||||||||||||||||||||||||||||
6th ionization potential | 9220 kJ/mol | ||||||||||||||||||||||||||||||||||||
7th ionization potential | 11500 kJ/mol | ||||||||||||||||||||||||||||||||||||
Most Stable Isotopes | |||||||||||||||||||||||||||||||||||||
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SI units & STP are used except where noted. |
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The most common oxidation states of manganese are +2, +3, +4, +6 and +7, though oxidation states from +1 to +7 are observed. Mn+2 often competes with Mg+2 in biological systems, and manganese compounds where manganese is in oxidation state +7 are powerful oxidizing agents.
Substitutes: Manganese has no satisfactory substitute in its major applications.
In the 17th century, the German chemist Glauber first produced permanganate, a useful laboratory reagent. By the mid 18th century, manganese oxide was in use in the manufacture of chlorine. The Swedish chemist Scheele was the first to recognize that manganese was an element, and his colleague, J. G. Gahn, isolated the pure element in 1774 by reduction of the dioxide with carbon. Around the beginning of the 19th century, scientists began exploring the use of manganese in steelmaking, with patents being granted for its use at the time. In 1816, it was noted that adding manganese to iron made it harder, without making it any more brittle.
Manganese is an essential trace nutrient in all forms of life.
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 best known manganese containing polypeptides may be arginase[?], Mn containing superoxide dismutase, and the diphtheria toxin.
US Import Sources (1998-2001): Manganese ore: Gabon, 70%; South Africa, 10%; Australia, 9%; Mexico, 5%; and other, 6%. Ferromanganese: South Africa, 47%; France, 22%; Mexico, 8%; Australia, 8%; and other, 15%. Manganese contained in all manganese imports: South Africa, 31%; Gabon, 21%; Australia, 13%; Mexico, 8%; and other, 27%.
Manganese is mined in Burkina Faso.
Vast quantities of manganese exist in manganese nodules[?] on the ocean floor[?]. Attempts to find economically viable methods of harvesting manganese nodules were abandoned in the 1970s.
Manganese dioxide is used in dry cells, and can be used to decolorize glass that is colored green by trace amounts of iron. Manganese compounds can color glass an amethyst color, and is responsible for the color of true amethyst. Manganese dioxide is also used in the manufacture of oxygen and chlorine, and in drying black paints.
Manganese is part of the iron group of elements which are thought to be synthesized in large stars shortly before supernova explosion. Manganese-53 decays to 53Cr with a half-life of 3.7 million years. Because of its relatively short half-life, 53Mn is an extinct radionuclide. Manganese isotopic contents are typically combined with chromium isotopic contents and have found application in isotope geology[?]. Mn-Cr isotopic ratios reinforce the evidence from 26Al and 107Pd for the early history of the solar system. Variations in 53Cr/52Cr and Mn/Cr ratios from several meteorites indicate an initial 53Mn/55Mn ratio that suggests Mn-Cr isotopic systematics must result from in-situ decay of 53Mn in differentiated planetary bodies. Hence 53Mn provides additional evidence for nucleosynthetic processes immediately before coalescence of the solar system.
The isotopes of manganese range in atomic weight from 46 amu (46-Mn) to 65 amu (65-Mn). The primary decay mode before the most abundant stable isotope, 55-Mn, is electron capture and the primary mode after is beta.
Acidic permanganate solutions will destroy any organic material they come in contact with, and can set them on fire.
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