Manganese

Manganese (Mn)

Grey brittle metallic transition element. Rather electropositive, combines with some non-metals when heated. Discovered in 1774 by Scheele.
Atomic Number25
Atomic Weight54.938044
Mass Number55
Group7
Period4
Blockd
Protons25 p+
Neutrons30 n0
Electrons25 e-
Manganese electrolytic and 1cm3 cube.jpg Animated Bohr Model Enhanced Bohr Model Bohr Model Orbital Diagram

Properties

Atomic Radius
140 pm
Atomic Volume
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 shell2, 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 StructureBody Centered Cubic (CUB)
Lattice Constant
8.89 Å
Bulk Modulus
Electrical Resistivity
Electron Configuration[Ar] 3d5 4s2
Magnetic Ordering
Magnetic Susceptibility
PhaseSolid
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
CategoryTransition metals, Transition metals
CAS GroupVIIA
IUPAC GroupVIIB
Glawe Number72
Mendeleev Number55
Pettifor Number60
Geochemical Classfirst series transition metal
Goldschmidt Classsiderophile
Radioactivity
RadioactiveNo
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 Universe0.0008%

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

DiscoverersJohann Gahn
Discovery LocationSweden
Discovery Year1774
Name OriginLatin: 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.