Manganese (Mn)
Grey brittle metallic transition element. Rather electropositive, combines with some non-metals when heated. Discovered in 1774 by Scheele.
| Atomic Number | 25 |
|---|---|
| Atomic Weight | 54.938044 |
| Mass Number | 55 |
| Group | 7 |
|---|---|
| Period | 4 |
| Block | d |
| Protons | 25 p+ |
|---|---|
| Neutrons | 30 n0 |
| Electrons | 25 e- |
Properties
| Atomic Radius | 140 pm
|
|---|---|
| Atomic Volume | 7.39 cm³/mol
|
| Covalent Radius | 119 pm
|
| Metallic Radius | 118 pm
|
| Ionic Radius | 66 pm
|
| Crystal Radius | 80 pm
|
| Van der Waals radius |
204.99999999999997 pm
|
| Density | 7.3 g/cm³
|
| Boiling Point | 2,235 K
|
| Melting Point | 1,517 K
|
| Electrons per shell | 2, 8, 13, 2 |
| Electronegativity |
1.55
|
| Electrophilicity | |
| Proton Affinity | 797.3 kJ/mol
|
| Electron Affinity | |
| Ionization Potential | 7.434018 eV/particle
|
| Heat of Vaporization | 221 kJ/mol
|
| Heat of Fusion | 13.4 kJ/mol
|
| Heat of Formation | 283.3 kJ/mol
|
| Molar Heat Capacity | 26.32 J/(mol K)
|
| Specific Heat Capacity | 0.479 J/(g⋅K)
|
| Thermal Conductivity | |
| Gas Basicity | 774.4 kJ/mol
|
| Dipole Polarizability | 68 a₀
|
| C6 Dispersion Coefficient | 552 a₀
|
| Oxidation States | -3, -2, -1, 1, 2, 3, 4, 5, 6, 7 |
| Color | Silver
|
| Crystal Structure | Body Centered Cubic (CUB) |
| Lattice Constant | 8.89 Å
|
| Bulk Modulus | |
| Electrical Resistivity | |
| Electron Configuration | [Ar] 3d5 4s2 |
| Magnetic Ordering | |
| Magnetic Susceptibility | |
| Phase | Solid |
| Poisson Ratio | |
| Shear Modulus | |
| Young's Modulus | |
| Allotropes | |
| Alternate Names | |
| Adiabatic Index | |
| Appearance | |
| Electric Conductivity | |
| Critical Pressure | |
| Critical Temperature | |
| Curie Point | |
| Electrical | |
| Hardness | |
| Magnetic Susceptibility | |
| Magnetic | |
| Neel Point | |
| Neutron Cross Section | |
| Neutron Mass Absorption | |
| Gas Phase | |
| Quantum Numbers | |
| Refractive Index | |
| Space Group | |
| Speed of Sound | |
| Superconducting Point | |
| Thermal Expansion | |
| Valence Electrons | |
| Classification | |
| Category | Transition metals, Transition metals |
| CAS Group | VIIA |
| IUPAC Group | VIIB |
| Glawe Number | 72 |
| Mendeleev Number | 55 |
| Pettifor Number | 60 |
| Geochemical Class | first series transition metal |
| Goldschmidt Class | siderophile |
| Radioactivity | |
| Radioactive | No |
| Decay Mode | |
| Half-Life | |
| Lifetime | |
| Abundance | |
| Abundance in Earth's crust | 950 mg/kg
|
| Abundance in Oceans | 0.0002 mg/L
|
| Abundance in Human Body | |
| Abundance in Meteor | |
| Abundance in Sun | |
| Abundance in Universe | 0.0008% |
Isotopes of Manganese
Stable Isotopes
55Mn
Unstable Isotopes
44Mn 45Mn 46Mn 47Mn 48Mn 49Mn 50Mn 51Mn 52Mn 53Mn 54Mn 56Mn 57Mn 58Mn 59Mn 60Mn 61Mn 62Mn 63Mn 64Mn 65Mn 66Mn 67Mn 68Mn 69Mn
History
By the mid-18th century, Swedish chemist Carl Wilhelm Scheele had used pyrolusite to produce chlorine. Scheele and others were aware that pyrolusite contained a new element, but they were not able to isolate it. Johan Gottlieb Gahn was the first to isolate an impure sample of manganese metal in 1774, by reducing the dioxide with carbon. From the Latin word magnes, magnet, from magnetic properties of pyrolusite
| Discoverers | Johann Gahn |
|---|---|
| Discovery Location | Sweden |
| Discovery Year | 1774 |
| Name Origin | Latin: magnes (magnet); Italian: manganese. |
Excess manganese, particularly inhalation of the powder, is toxic
Neanderthals may have used black manganese di oxide as a cosmetic 50,000 years ago
Uses
For over 2000 years, manganese dioxide has been used to make colorless glass. Manganese dioxide is used as the cathode material in zinc-carbon and alkaline batteries. Manganese also functions in the oxygen-evolving complex of photosynthetic plants. The dioxide is also used in the preparation of oxygen and chlorine and in drying black paints. Used in steel, batteries and ceramics. The steel in railroad tracks can contain as much as 1.2% manganese. It is crucial to the effectiveness of vitamin B1.
Sources
Most abundant ores are pyrolusite (MnO2), psilomelane [(Ba,H2O)2Mn5O10] and rhodochrosite (MnCO3). Pure metal produced by mixing MnO2 with powered Al and ignited in a furnace.