Crossword clues for manganese
Longman Dictionary of Contemporary English
The Collaborative International Dictionary
Mn \Mn\, n. (Chem.) The chemical symbol for manganese.
Manganese \Man`ga*nese"\, n. [F. mangan[`e]se, It. manganese, sasso magnesio; prob. corrupted from L. magnes, because of its resemblance to the magnet. See Magnet, and cf. Magnesia.] (Chem.) An element obtained by reduction of its oxide, as a hard, grayish white metal, fusible with difficulty (melting point 1244[deg] C), but easily oxidized. Its ores occur abundantly in nature as the minerals pyrolusite, manganite, etc. Symbol Mn. Atomic number 25; Atomic weight 54.938 [C=12.011].
Note: An alloy of manganese with iron (called ferromanganese) is used to increase the density and hardness of steel.
Black oxide of manganese, Manganese dioxide or Manganese peroxide, or Black manganese (Chem.), a heavy black powder MnO2, occurring native as the mineral pyrolusite, and valuable as a strong oxidizer; -- called also familiarly manganese. It colors glass violet, and is used as a decolorizer to remove the green tint of impure glass.
Douglas Harper's Etymology Dictionary
1670s as the name of a mineral, oxide of manganese, from French manganèse (16c.), from Italian manganese, alteration or corruption of Medieval Latin magnesia (see magnesia). From 1783 in English as the name of an element.
n. A metallic chemical element (''symbol'' Mn) with an atomic number of 25.
n. a hard brittle gray polyvalent metallic element that resembles iron but is not magnetic; used in making steel; occurs in many minerals [syn: Mn, atomic number 25]
Manganese is a chemical element with symbol Mn and atomic number 25. It is not found as a free element in nature; it is often found in minerals in combination with iron. Manganese is a metal with important industrial metal alloy uses, particularly in stainless steels.
Historically, manganese is named for various black minerals (such as pyrolusite) from the same region of Magnesia in Greece which gave names to similar-sounding magnesium, Mg, and magnetite, an ore of the element iron, Fe. By the mid-18th century, Swedish chemist Carl Wilhelm Scheele had used pyrolusite to produce chlorine. Scheele and others were aware that pyrolusite (now known to be manganese dioxide) contained a new element, but they were unable to isolate it. Johan Gottlieb Gahn was the first to isolate an impure sample of manganese metal in 1774, which he did by reducing the dioxide with carbon.
Manganese phosphating is used for rust and corrosion prevention on steel. Ionized manganese is used industrially as pigments of various colors, which depend on the oxidation state of the ions. The permanganates of alkali and alkaline earth metals are powerful oxidizers. Manganese dioxide is used as the cathode (electron acceptor) material in zinc-carbon and alkaline batteries.
In biology, manganese(II) ions function as cofactors for a large variety of enzymes with many functions. Manganese enzymes are particularly essential in detoxification of superoxide free radicals in organisms that must deal with elemental oxygen. Manganese also functions in the oxygen-evolving complex of photosynthetic plants. The element is a required trace mineral for all known living organisms but is a neurotoxin. In larger amounts, and apparently with far greater effectiveness through inhalation, it can cause a poisoning in mammals with neurological damage that is sometimes irreversible.
Manganese is a chemical element.
Manganese may also refer to:
- Manganese, Minnesota, a ghost town
- Manganese, West Virginia
- SS Manganese, a steamship
- A derogatory term for Japanese People (a portmanteau of Manga and Japanese)
Usage examples of "manganese".
Magnesium, aluminium, iron, zinc, nickel, cobalt, manganese, and cadmium dissolve, with evolution of hydrogen, in the cold acid, or when warmed.
In the absence of manganese and cobalt the titration may be made without further separation.
It may be removed by passing sulphuretted hydrogen through the filtrate from the acetate separation: sulphides of nickel, cobalt and zinc will be precipitated, whilst manganese remains in solution: the addition of more sodium acetate may assist the precipitation.
The solution will contain the zinc, together with any manganese the ore contained, and, perhaps, traces of nickel and cobalt.
The oxide of manganese will be precipitated, and can be ignited and weighed.
To the hydrochloric acid solution of the zinc and manganese add sodium acetate in large excess and pass sulphuretted hydrogen freely.
The precipitate, freed from manganese, is then dissolved in hydrochloric acid and titrated.
Generally a small, but decided, precipitate of alumina comes down, together with sulphides of any zinc or manganese which is present.
If the percentage of dioxide is required it may be calculated by multiplying the percentage of manganese by 1.
It must be borne in mind that the manganese should never be calculated to dioxide except when it is known to exist in the ore only in that form.
The depth of colour depends on the amount of manganese present, and this should not much exceed 10 milligrams.
A quantity of substance containing not more than this amount of manganese should be boiled for a few minutes with 25 c.
The manganese is determined in the titrated solution by precipitation as dioxide and titrating.
If the dishes show a manganese stain, wash them out with a few drops of hydrochloric and sulphurous acids.
Copper, Silver, Gold, Zinc and Cadmium, Mercury, Tin, Lead, Bismuth, Antimony, Chromium, Molybdenum, Tungsten, Uranium, Manganese, Iron, Nickel, and Cobalt, the Platinum Group.