Element Information, Facts, Properties, Trends, Uses, Comparison with other elements
Cobalt is a chemical element with symbol Co and atomic number 27. Like nickel, cobalt in the Earth's crust is found only in chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal.
It belongs to group 9 of the periodic table having trivial name .
Read key information and facts about element Cobalt
|Appearance||hard lustrous gray metal|
|Group in Periodic Table||9|
|Group Name||cobalt family|
|Period in Periodic Table||period 4|
|Block in Periodic Table||d -block|
|Electronic Configuration||[Ar] 3d7 4s2|
|Electronic Shell Structure (Electrons per shell)||2, 8, 15, 2|
|Melting Point||1768 K|
|Boiling Point||3200 K|
How to Locate Cobalt on Periodic Table
Periodic table is arranged by atomic number, number of protons in the nucleus which is same as number of electrons. The atomic number increases from left to right. Periodic table starts at top left ( Atomic number 1) and ends at bottom right (atomic number 118). Therefore you can directly look for atomic number 27 to find Cobalt on periodic table.
Another way to read periodic table and locate an element is by using group number (column) and period number (row). To locate Cobalt on periodic table look for cross section of group 9 and period 4 in the modern periodic table.
The element Cobalt was discovered by G. Brandt in year 1735 in Sweden. Cobalt was first isolated by G. Brandt in 1735. Cobalt derived its name from the German word Kobold, meaning 'goblin'.
Proved that the blue color of glass is due to a new kind of metal and not bismuth as thought previously.
Cobalt Presence: Abundance in Nature and Around Us
The table below shows the abundance of Cobalt in Universe, Sun, Meteorites, Earth's Crust, Oceans and Human Body.
|ppb by weight (1ppb =10^-7 %)||ppb by atoms (1ppb =10^-7 %)|
|Abundance in Universe||3000||60|
|Abundance in Sun||4000||70|
|Abundance in Meteorites||600000||200000|
|Abundance in Earth's Crust||30000||10000|
|Abundance in Oceans||0.08||0.008|
|Abundance in Humans||20||2|
Crystal Structure of Cobalt
The solid state structure of Cobalt is Simple Hexagonal.
The Crystal structure can be described in terms of its unit Cell. The unit Cells repeats itself in three dimensional space to form the structure.
Unit Cell Parameters
The unit cell is represented in terms of its lattice parameters, which are the lengths of the cell edges Lattice Constants (a, b and c)
|250.71 pm||250.71 pm||406.95 pm|
and the angles between them Lattice Angles (alpha, beta and gamma).
The positions of the atoms inside the unit cell are described by the set of atomic positions ( xi, yi, zi) measured from a reference lattice point.
The symmetry properties of the crystal are described by the concept of space groups. All possible symmetric arrangements of particles in three-dimensional space are described by the 230 space groups (219 distinct types, or 230 if chiral copies are considered distinct.
|Space Group Name||P63/mmc|
|Oxidation States||Space Group Number||194|
|Crystal Structure||Simple Hexagonal|
Cobalt Atomic and Orbital Properties
Cobalt atoms have 27 electrons and the electronic shell structure is [2, 8, 15, 2] with Atomic Term Symbol (Quantum Numbers) 4F9/2.
|Number of Electrons (with no charge)||27|
|Number of Protons||27|
|Number of Neutrons||32|
|Shell structure (Electrons per energy level)||2, 8, 15, 2|
|Electron Configuration||[Ar] 3d7 4s2|
|Valence Electrons||3d7 4s2|
|Main Oxidation States||2, 3|
|Oxidation States||-3, -1, 0, 1, 2, 3, 4, 5|
|Atomic Term Symbol (Quantum Numbers)||4F9/2|
Bohr Atomic Model of Cobalt - Electrons per energy level
Ground State Electronic Configuration of Cobalt - neutral Cobalt atom
Abbreviated electronic configuration of Cobalt
The ground state abbreviated electronic configuration of Neutral Cobalt atom is [Ar] 3d7 4s2. The portion of Cobalt configuration that is equivalent to the noble gas of the preceding period, is abbreviated as [Ar]. For atoms with many electrons, this notation can become lengthy and so an abbreviated notation is used. This is important as it is the Valence electrons 3d7 4s2, electrons in the outermost shell that determine the chemical properties of the element.
Unabbreviated electronic configuration of neutral Cobalt
Complete ground state electronic configuration for the Cobalt atom, Unabbreviated electronic configuration
1s2 2s2 2p6 3s2 3p6 3d7 4s2
Electrons are filled in atomic orbitals as per the order determined by the Aufbau principle, Pauli Exclusion Principle and Hund’s Rule.
Atomic Structure of Cobalt
Cobalt atomic radius is 152 pm, while it's covalent radius is 126 pm.
|Atomic Radius Calculated|
152 pm (1.52 Å)
|Atomic Radius Empirical|
135 pm (1.35 Å)
|Atomic Volume||6.62 cm3/mol|
|Covalent Radius||126 pm (1.26 Å)|
|Van der Waals Radius||-|
|Neutron Cross Section||37.2|
|Neutron Mass Absorption||0.021|
Atomic Spectrum of Cobalt
Cobalt Chemical Properties: Cobalt Ionization Energies and electron affinity
The electron affinity of Cobalt is 63.7 kJ/mol.
Ionization Energy of Cobalt
Refer to table below for Ionization energies of Cobalt
|Ionization energy number||Enthalpy - kJ/mol|
Cobalt Physical Properties
Refer to below table for Cobalt Physical Properties
|Density||8.9 g/cm3(when liquid at m.p density is $7.75 g/cm3)|
|Molar Volume||6.62 cm3/mol|
|Shear Modulus||75 GPa|
|Bulk Modulus||180 GPa|
Hardness of Cobalt - Tests to Measure of Hardness of Element
|Mohs Hardness||5 MPa|
|Vickers Hardness||1043 MPa|
|Brinell Hardness||700 MPa|
Cobalt Electrical Properties
Cobalt is Conductor of electricity. Refer to table below for the Electrical properties ofCobalt
|Electrical Conductivity||17000000 S/m|
|Resistivity||6e-8 m Ω|
Cobalt Heat and Conduction Properties
|Thermal Conductivity||100 W/(m K)|
|Thermal Expansion||0.000013 /K|
Cobalt Magnetic Properties
|Curie Point||1394 K|
|Mass Magnetic Susceptibility||-|
|Molar Magnetic Susceptibility||-|
|Volume Magnetic Susceptibility||-|
Optical Properties of Cobalt
Acoustic Properties of Cobalt
|Speed of Sound||4720 m/s|
Cobalt Thermal Properties - Enthalpies and thermodynamics
Refer to table below for Thermal properties of Cobalt
|Melting Point||1768 K (1494.85°C, 2722.73 °F)|
|Boiling Point||3200 K (2926.85°C, 5300.33 °F)|
Enthalpies of Cobalt
|Heat of Fusion||16.2 kJ/mol|
|Heat of Vaporization||375 kJ/mol|
|Heat of Combustion||-|
Cobalt Isotopes - Nuclear Properties of Cobalt
Cobalt has 29 isotopes, with between 47 and 75 nucleons. Cobalt has 1 stable naturally occuring isotopes.
Isotopes of Cobalt - Naturally occurring stable Isotopes: 59Co.
|Isotope||Z||N||Isotope Mass||% Abundance||T half||Decay Mode|