Manganese

Manganese, ₂₅Mn
	Pure manganese cube and oxidized manganese chips
Manganese
Pronunciation	/ˈmæŋɡəniːz/ (MANG-gə-neez)
Appearance	silvery metallic
Standard atomic weight Ar°(Mn)
	54.938043±0.000002; 54.938±0.001 (abridged);
Manganese in the periodic table
	chromium ← manganese → iron
Atomic number (Z)	25
Group	group 7
Period	period 4
Block	d-block
Electron configuration	[Ar] 3d5 4s2
Electrons per shell	2, 8, 13, 2
Physical properties
Phase at STP	solid
Melting point	1519 K (1246 °C, 2275 °F)
Boiling point	2334 K (2061 °C, 3742 °F)
Density (at 20° C)	7.476 g/cm3
when liquid (at m.p.)	5.95 g/cm3
Heat of fusion	12.91 kJ/mol
Heat of vaporization	221 kJ/mol
Molar heat capacity	26.32 J/(mol·K)
Atomic properties
Oxidation states	common: +2, +4, +7; −3, −1, 0,? +1,, +3, +5,, +6
Electronegativity	Pauling scale: 1.55
Ionization energies	1st: 717.3 kJ/mol ; 2nd: 1509.0 kJ/mol ; 3rd: 3248 kJ/mol ; (more) ;
Atomic radius	empirical: 127 pm
Covalent radius	Low spin: 139±5 pm; High spin: 161±8 pm
	Spectral lines of manganese
Other properties
Natural occurrence	primordial
Crystal structure	α-Mn: body-centered cubic (bcc) (cI58)
Lattice constant	a = 891.16 pm (at 20 °C)
Thermal expansion	23.61×10−6/K (at 20 °C)
Thermal conductivity	7.81 W/(m⋅K)
Electrical resistivity	1.44 µΩ⋅m (at 20 °C)
Magnetic ordering	paramagnetic
Molar magnetic susceptibility	(α) +529.0×10−6 cm3/mol (293 K)
Young's modulus	198 GPa
Bulk modulus	120 GPa
Speed of sound thin rod	5150 m/s (at 20 °C)
Mohs hardness	6.0
Brinell hardness	196 MPa
CAS Number	7439-96-5
History
Discovery	Carl Wilhelm Scheele (1774)
First isolation	Johann Gottlieb Gahn (1774)
Isotopes of manganese v; e;
β−	54Fe
β+	54Cr
	Category: Manganese; view; talk; edit; \| references

Manganese is a chemical element; it has symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese was first isolated in the 1770s. It is a transition metal with a multifaceted array of industrial alloy uses, particularly in stainless steels. It improves strength, workability, and resistance to wear. Manganese oxide is used as an oxidising agent; as a rubber additive; and in glass making, fertilisers, and ceramics. Manganese sulfate can be used as a fungicide.

Manganese is also an essential human dietary element, important in macronutrient metabolism, bone formation, and free radical defense systems. It is a critical component in dozens of proteins and enzymes.^[7] It is found mostly in the bones, but also the liver, kidneys, and brain.^[8] In the human brain, the manganese is bound to manganese metalloproteins, most notably glutamine synthetase in astrocytes.

It is familiar in the laboratory in the form of the deep violet salt potassium permanganate. It occurs at the active sites in some enzymes.^[9] Of particular interest is the use of a Mn-O cluster, the oxygen-evolving complex, in the production of oxygen by plants.

^ "Standard Atomic Weights: Manganese". CIAAW. 2017.
^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (4 May 2022). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
^ ^a ^b ^c Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
^ ^a ^b ^c ^d ^e ^f Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 28. ISBN 978-0-08-037941-8.
^ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
^ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
^ Cite error: The named reference Erikson-2019 was invoked but never defined (see the help page).
^ Cite error: The named reference Emsley2001 was invoked but never defined (see the help page).
^ Roth, Jerome; Ponzoni, Silvia; Aschner, Michael (2013). "Manganese Homeostasis and Transport". In Banci, Lucia (ed.). Metallomics and the Cell. Metal Ions in Life Sciences. Vol. 12. Springer. pp. 169–201. doi:10.1007/978-94-007-5561-1_6. ISBN 978-94-007-5560-4. PMC 6542352. PMID 23595673. Electronic-book ISBN 978-94-007-5561-1.

[1] "Standard Atomic Weights: Manganese". CIAAW. 2017.

[CIAAW2021-2] Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (4 May 2022). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.

[Arblaster_2018-3] Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.

[GE28-4] ^ ^a ^b ^c ^d ^e ^f Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 28. ISBN 978-0-08-037941-8.

[5] Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.

[NUBASE2020-6] Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.

[Erikson-2019-7] Cite error: The named reference Erikson-2019 was invoked but never defined (see the help page).

[Emsley2001-8] Cite error: The named reference Emsley2001 was invoked but never defined (see the help page).

[9] Roth, Jerome; Ponzoni, Silvia; Aschner, Michael (2013). "Manganese Homeostasis and Transport". In Banci, Lucia (ed.). Metallomics and the Cell. Metal Ions in Life Sciences. Vol. 12. Springer. pp. 169–201. doi:10.1007/978-94-007-5561-1_6. ISBN 978-94-007-5560-4. PMC 6542352. PMID 23595673. Electronic-book ISBN 978-94-007-5561-1.

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