MANGANESE

Introduction

Atomic Number: 25
Group: 7 or VII B
Atomic Weight: 54.938049
Period: 4
CAS Number: 7439-96-5

Classification

Chalcogen
Halogen
Noble Gas
Lanthanoid
Actinoid
Rare Earth Element
Platinum Group Metal
Transuranium
No Stable Isotopes
Solid
Liquid
Gas
Solid (Predicted)

Description • Uses/Function

Recognized by Scheele, Bergman,and others as an element and isolated by Gahn in 1774 by reduction of the dioxide with carbon. Manganese minerals are widely distributed; oxides,silicates, and carbonates are the most common. The discovery of large quantities of manganese nodules on the floor of the oceans holds promise asa source of manganese. These nodules contain about 24% manganese together with many other elements in lesser abundance. Most manganese todayis obtained from ores found in the Ukraine, Brazil, Australia, Republic of South Africa, Gabon, China, and India. Pyrolusite (MnO2) and rhodochrosite(MnCO3) are among the most common manganese minerals. The metal is obtained by reduction of the oxide with sodium, magnesium, aluminum,or by electrolysis. It is gray-white, resembling iron, but is harder and very brittle. The metal is reactive chemically, and decomposes cold water slowly.Manganese is used to form many important alloys. In steel, manganese improves the rolling and forging qualities, strength, toughness, stiffness, wearresistance, hardness, and hardenability. With aluminum and antimony, especially with small amounts of copper, it forms highly ferromagnetic alloys.Manganese metal is ferromagnetic only after special treatment. The pure metal exists in four allotropic forms. The alpha form is stable at ordinarytemperature; gamma manganese, which changes to alpha at ordinary temperatures, is said to be flexible, soft, easily cut, and capable of being bent.The dioxide (pyrolusite) is used as a depolarizer in dry cells, and is used to “decolorize” glass that is colored green by impurities of iron. Manganeseby itself colors glass an amethyst color, and is responsible for the color of true amethyst. The dioxide is also used in the preparation of oxygen andchlorine, and in drying black paints. The permanganate is a powerful oxidizing agent and is used in quantitative analysis and in medicine. Manganeseis widely distributed throughout the animal kingdom. It is an important trace element and may be essential for utilization of vitamin B1. Twenty threeisotopes and isomers are known. Manganese metal (99.95%) is priced at about $400/kg. Metal of 99.6% purity is priced at about $60/kg. 1

• "like vanadium and chromium, is used mostly to make steel alloys." 2
• "...is an important element in steels that must withstand great shock, such as those used to construct rock crushers." 3
• "enzymes, bone…essential for enzymes in humans and other animals" 4
• "The metal is used in alloys with iron5

Physical Properties

Melting Point:6*  1246 °C = 1519.15 K = 2274.8 °F
Boiling Point:6* 2061 °C = 2334.15 K = 3741.8 °F
Sublimation Point:6 
Triple Point:6 
Critical Point:6 
Density:7  7.3 g/cm3

* - at 1 atm

Electron Configuration

Electron Configuration: [Ar] 4s2 3d5
Block: d
Highest Occupied Energy Level: 4
Valence Electrons: 

Quantum Numbers:

n = 3
ℓ = 2
m = 2
ms = +½

Bonding

Electronegativity (Pauling scale):8 1.55
Electropositivity (Pauling scale): 2.45
Electron Affinity:9 not stable eV
Oxidation States: +2,3,4,6,7
Work Function:10 3.90 eV = 6.2478E-19 J

Ionization Potential   eV 11  kJ/mol  
1 7.43402    717.3
2 15.63999    1509.0
3 33.668    3248.5
4 51.2    4940.0
5 72.4    6985.5
6 95.6    9224.0
7 119.203    11501.3
8 194.5    18766.4
Ionization Potential   eV 11  kJ/mol  
9 221.8    21400.4
10 248.3    23957.3
11 286    27594.8
12 314.4    30335.0
13 343.6    33152.4
14 403    38883.6
15 435.163    41986.8
16 1134.7    109481.9
Ionization Potential   eV 11  kJ/mol  
17 1224    118098.0
18 1317    127071.2
19 1437    138649.4
20 1539    148490.9
21 1644    158621.8
22 1788    172515.7
23 1879.9    181382.7
24 8140.6    785448.3
25 8571.94    827066.3

Thermochemistry

Specific Heat: 0.479 J/g°C 12 = 26.315 J/mol°C = 0.114 cal/g°C = 6.290 cal/mol°C
Thermal Conductivity: 7.82 (W/m)/K, 27°C 13
Heat of Fusion: 12.05 kJ/mol 14 = 219.3 J/g
Heat of Vaporization: 266 kJ/mol 15 = 4841.8 J/g
State of Matter Enthalpy of Formation (ΔHf°)16 Entropy (S°)16 Gibbs Free Energy (ΔGf°)16
(kcal/mol) (kJ/mol) (cal/K) (J/K) (kcal/mol) (kJ/mol)
(s alpha) 0 0 7.65 32.0076 0 0
(s gamma) 0.37 1.54808 7.75 32.426 0.34 1.42256
(g) 67.1 280.7464 41.49 173.59416 57.0 238.488

Isotopes

Nuclide Mass 17 Half-Life 17 Nuclear Spin 17 Binding Energy
44Mn 44.00687(54)# <105 ns (2-)# 329.99 MeV
45Mn 44.99451(32)# <70 ns (7/2-)# 349.24 MeV
46Mn 45.98672(12)# 37(3) ms (4+) 364.76 MeV
47Mn 46.97610(17)# 100(50) ms 5/2-# 382.15 MeV
48Mn 47.96852(12) 158.1(22) ms 4+ 397.67 MeV
49Mn 48.959618(26) 382(7) ms 5/2- 414.13 MeV
50Mn 49.9542382(11) 283.29(8) ms 0+ 426.86 MeV
51Mn 50.9482108(11) 46.2(1) min 5/2- 440.52 MeV
52Mn 51.9455655(21) 5.591(3) d 6+ 451.38 MeV
53Mn 52.9412901(9) 3.74(4)E+6 a 7/2- 463.18 MeV
54Mn 53.9403589(14) 312.03(3) d 3+ 472.18 MeV
55Mn 54.9380451(7) STABLE 5/2- 482.12 MeV
56Mn 55.9389049(7) 2.5789(1) h 3+ 490.19 MeV
57Mn 56.9382854(20) 85.4(18) s 5/2- 498.26 MeV
58Mn 57.93998(3) 3.0(1) s 1+ 505.40 MeV
59Mn 58.94044(3) 4.59(5) s (5/2)- 512.54 MeV
60Mn 59.94291(9) 51(6) s 0+ 518.75 MeV
61Mn 60.94465(24) 0.67(4) s (5/2)- 524.95 MeV
62Mn 61.94843(24) 671(5) ms (3+) 529.30 MeV
63Mn 62.95024(28) 275(4) ms 5/2-# 535.51 MeV
64Mn 63.95425(29) 88.8(25) ms (1+) 539.85 MeV
65Mn 64.95634(58) 92(1) ms 5/2-# 546.06 MeV
66Mn 65.96108(43)# 64.4(18) ms 549.48 MeV
67Mn 66.96414(54)# 45(3) ms 5/2-# 554.75 MeV
68Mn 67.96930(64)# 28(4) ms 558.17 MeV
69Mn 68.97284(86)# 14(4) ms 5/2-# 563.44 MeV
Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses. 17

Reactions

Abundance

Earth - Source Compounds: oxides 19
Earth - Seawater: 0.0002 mg/L 20
Earth -  Crust:  950 mg/kg = 0.095% 20
Earth -  Lithosphere:  0.11% 21
Earth -  Total:  750 ppm 22
Mercury -  Total:  150 ppm 22
Venus -  Total:  460 ppm 22
Chondrites - Total: 7400 (relative to 106 atoms of Si) 23
Human Body - Total: 0.00002% 24

Compounds

Prices





Safety Information


Material Safety Data Sheet - ACI Alloys, Inc.

For More Information

External Links:

Sources

(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:18-4:19.
(2) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill: New York, 2006; p 1013.
(3) - Whitten, Kenneth W., Davis, Raymond E., and Peck, M. Larry. General Chemistry 6th ed.; Saunders College Publishing: Orlando, FL, 2000; p 903.
(4) - Whitten, Kenneth W., Davis, Raymond E., and Peck, M. Larry. General Chemistry 6th ed.; Saunders College Publishing: Orlando, FL, 2000; p 926-7.
(5) - Swaddle, T.W. Inorganic Chemistry; Academic Press: San Diego, 1997; p 8.
(6) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:132.
(7) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 4:39-4:96.
(8) - Dean, John A. Lange's Handbook of Chemistry, 11th ed.; McGraw-Hill Book Company: New York, NY, 1973; p 4:8-4:149.
(9) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 10:147-10:148.
(10) - Speight, James. Lange's Handbook of Chemistry, 16th ed.; McGraw-Hill Professional: Boston, MA, 2004; p 1:132.
(11) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10:178 - 10:180.
(12) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:133.
(13) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(14) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(15) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(16) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(17) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).
(18) - Ebbing, Darrell D. General Chemistry 3rd ed.; Houghton Mifflin Company: Boston, MA, 1990; p 206.
(19) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 965.
(20) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14:17.
(21) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 964.
(22) - Morgan, John W. and Anders, Edward, Proc. Natl. Acad. Sci. USA 77, 6973-6977 (1980)
(23) - Brownlow, Arthur. Geochemistry; Prentice-Hall, Inc.: Englewood Cliffs, NJ, 1979, pp 15-16.
(24) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 7:17.