Manganese

1770-1774 Manganese

The book of science

Tom Sharp

Uppsala, FalunTorbern Bergman, Carl Wilhelm Scheele, Johan Gottlieb Gahn elements Manganese

Manganese

Torbern Bergman investigated pyrolusite, a mineral containing manganese dioxide, distinguishing it from known elements including lime and magnesia alba, but was unable to isolate the element. His friend Carl Wilhelm Scheele used pyrolusite, as an oxydizing agent to produce chlorine and knew it contained a new element, giving it the name maganese, but was also unable to isolate it. Johan Gottlieb Gahn, Bergman’s former assistant, was able to isolate the element from the mineral by reducing the dioxide with carbon to obtain this hard brittle silvery metal.

Atomic number 25

Pyrolusite, also known as magnesia negra, was found, like magnesium ore, in Magnesia, and was used as a pigment in cave paintings and to remove color from glass. * Manganese ores are pyrolusite, braunite, psilomelane, and rhodochrosite. Manganese minerals include manganite, purpurite, and rhodonite, and manganese occurs in the iron ore spiegeleisen. * Manganese occurs naturally in some iron ores, particularly ores used to make Spartan steel in Greece, which made it stronger but not more brittle and led to widespread use in steels. * A small amount of manganese is alloyed with aluminum to make aluminum cans. A manganese compound replaces lead in gasoline to reduce engine knocking. * Manganese is a required trace mineral, a cofactor in many enzymes. Manganese dioxide is used as a cathode in batteries, and a manganese phosphate coating on steel prevents corrosion and rust.

Manganism

Chronic overexposure to manganese results in physical and psychiatric disturbances, and maybe vocabulary confusion. Manganism is totally unrelated to the effects of Japanese comic books, manga, and has nothing to do with the mangonel, a kind of catapult, or magnetite, magnets, magnetism, or magnesium, just becauses their ores and lodestones were found in Magnesia. You are in no danger of contracting the syndrome by overeating mangos, or by swallowing too much milk of magnesia, or by being magnanimous, or having more than one manager, or seeing babies in mangers. The first three letters of manganism are not a prefix; the syndrome is unrelated to the male gender, specifically. Manganese is not a language spoken near Rio Manga in Honduras. But we are beginning to suspect that in many cases manganism is undiagnosed due to the rareness of the condition.

“Symptoms include apathy, bradykinesia, gait disorder with postural instability, and spastic-hypokinetic dysarthria.”

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