Manganese

Manganese, ₂₅Mn
Manganese
Pronunciation	/ˈmæŋɡəniːz/ (MANG-gə-neez)
Appearance	silvery metallic
Standard atomic weight Ar, std(Mn)	54.938043(2)
Manganese in the periodic cairt
	chromium ← manganese → iron
Atomic nummer (Z)	25
Group	group 7
Period	period 4
Block	d-block
Element category	Transeetion metal
Electron confeeguration	[Ar] 3d5 4s2
Electrons per shell	2, 8, 13, 2
Pheesical properties
Phase at STP	solit
Meltin pynt	1519 K (1246 °C, 2275 °F)
Bylin pynt	2334 K (2061 °C, 3742 °F)
Density (near r.t.)	7.21 g/cm3
when liquid (at m.p.)	5.95 g/cm3
Heat o fusion	12.91 kJ/mol
Heat o vapourisation	221 kJ/mol
Molar heat capacity	26.32 J/(mol·K)
Atomic properties
Oxidation states	−3, −2, −1, 0, +1, +2, +3, +4, +5, +6, +7 (dependin on the oxidation state, an acidic, basic, or amphoteric oxide)
Electronegativity	Pauling scale: 1.55
Ionisation energies	(more);
Atomic radius	empirical: 127 pm
Covalent radius	139±5 (low spin), 161±8 (high spin) pm
	Colour lines in a spectral rangeSpectral lines o manganese
Ither properties
Naitural occurrence	primordial
Creestal structur	body-centred cubic (bcc)
Speed o soond thin rod	5150 m/s (at 20 °C)
Thermal expansion	21.7 µm/(m·K) (at 25 °C)
Thermal conductivity	7.81 W/(m·K)
Electrical resistivity	1.44 µ Ω·m (at 20 °C)
Magnetic orderin	paramagnetic
Young's modulus	198 GPa
Bulk modulus	120 GPa
Mohs haurdness	6.0
Brinell haurdness	196 MPa
CAS Nummer	7439-96-5
History
Diskivery	Torbern Olof Bergman (1770)
First isolation	Johann Gottlieb Gahn (1774)
Main isotopes o manganese
β+	52Cr
γ	-
γ	-
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Manganese is a chemical element, designated bi the seembol Mn. It haes the atomic nummer 25. It is foond as a free element in naitur (eften in combination wi iron), an in mony meenerals. Manganese is a metal wi important industrial metal alloy uises, parteecularly in stainless steels.

Historically, manganese is named for pyrolusite an ither black meenerals frae the region o Magnesia in Greece, that an aw gae its name tae magnesium an the airn ure magnetite. Bi the mid-18th century, Swadish-German chemist Carl Wilhelm Scheele haed uised pyrolusite tae produce chlorine. Scheele an ithers war awaur that pyrolusite (nou kent tae be manganese dioxide) conteened a new element, but thay war unable tae isolate it. Johan Gottlieb Gahn wis the first tae isolate an impure saumple o manganese metal in 1774, that he did bi reducin the dioxide wi caurbon.

Manganese phosphating is uised for roust an corrosion prevention on steel. Ionised manganese is uised industrially as pigments o various colours, that depend on the oxidation state o the ions. The permanganates o alkali an alkaline yird metals are pouerfu oxidisers. Manganese dioxide is uised as the cathode (electron acceptor) material in zinc-carbon an alkaline batteries.

In biology, manganese(II) ions function as cofactors for a muckle variety o enzymes wi mony functions.^[2] Manganese enzymes are pairteecularly essential in detoxification o superoxide free radicals in organisms that maun deal wi elemental oxygen. Manganese an aw functions in the oxygen-evolvin complex o photosynthetic plants. While the element is a required trace meeneral for aw kent leevin organisms, it an aw acts as a neurotoxin in muckler amoonts. Espeicially throu inhalation, it can cause manganism, a condeetion in mammals leadin tae neurological damage that is whiles irreversible.

References

↑ Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
↑ Roth, Jerome; Ponzoni, Silvia; Aschner, Michael (2013). "Chapter 6 Manganese Homeostasis and Transport". In Banci, Lucia (ed.). Metallomics and the Cell. Metal Ions in Life Sciences. 12. Springer. doi:10.1007/978-94-007-5561-1_6. ISBN 978-94-007-5560-4. electronic-book ISBN 978-94-007-5561-1

[CIAAW2013-1] Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.

[2] Roth, Jerome; Ponzoni, Silvia; Aschner, Michael (2013). "Chapter 6 Manganese Homeostasis and Transport". In Banci, Lucia (ed.). Metallomics and the Cell. Metal Ions in Life Sciences. 12. Springer. doi:10.1007/978-94-007-5561-1_6. ISBN 978-94-007-5560-4. electronic-book ISBN 978-94-007-5561-1

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