Tb - Terbium
Terbium Element Information, Facts, Properties, Trends, Uses, Comparison with other elements
Terbium is a chemical element with symbol Tb and atomic number 65. It is a silvery-white rare earth metal that is malleable, ductile and soft enough to be cut with a knife. Terbium is never found in nature as a free element, but it is contained in many minerals, including cerite, gadolinite, monazite, xenotime and euxenite.
It belongs to group null of the periodic table having trivial name . You can also download Printable Periodic Table of Elements Flashcards for Terbium in a PDF format.
Terbium Facts
Read key information and facts about element Terbium
| Name | Terbium |
| Atomic Number | 65 |
| Atomic Symbol | Tb |
| Atomic Weight | 158.92534 |
| Phase | Solid |
| Color | Silver |
| Appearance | silvery white |
| Classification | Lanthanide |
| Natural Occurance | Primordial |
| Group in Periodic Table | - |
| Group Name | |
| Period in Periodic Table | period 6 |
| Block in Periodic Table | f-block |
| Electronic Configuration | [Xe] 4f9 6s2 |
| Electronic Shell Structure (Electrons per shell) | 2, 8, 18, 27, 8, 2 |
| Melting Point | 1629 K |
| Boiling Point | 3503 K |
| CAS Number | CAS7440-27-9 |
How to Locate Terbium 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 65 to find Terbium 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 Terbium on periodic table look for cross section of group - and period 6 in the modern periodic table.
Terbium History
The element Terbium was discovered by G. Mosander in year 1842 in Sweden. Terbium was first isolated by J.C.G. de Marignac in 1886. Terbium derived its name from Ytterby, Sweden.
| Discovered By | G. Mosander |
| Discovery Date | 1842 in Sweden |
| First Isolation | 1886 |
| Isolated by | J.C.G. de Marignac |
In 1842 Mosander split yttria into two more earths, erbia and terbia.
Terbium Uses
Terbium is used as a stabilizer of high-temperature fuel cells. Its alloys are also used in electronic devices and as magnetic field indicators
Terbium Presence: Abundance in Nature and Around Us
The table below shows the abundance of Terbium 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 | 0.5 | 0.004 |
| Abundance in Sun | 0.1 | 0.001 |
| Abundance in Meteorites | 40 | 5 |
| Abundance in Earth's Crust | 940 | 120 |
| Abundance in Oceans | 0.00014 | 0.000005 |
| Abundance in Humans | - | - |
Crystal Structure of Terbium
The solid state structure of Terbium 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)
| a | b | c |
|---|---|---|
| 360.1 pm | 360.1 pm | 569.36 pm |
and the angles between them Lattice Angles (alpha, beta and gamma).
| alpha | beta | gamma |
|---|---|---|
| π/2 | π/2 | 2 π/3 |
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 |
| Space Group Number | 194 |
| Crystal Structure | Simple Hexagonal |
| Number of atoms per unit cell |
The number of atoms per unit cell in a simple cubic, face-centered cubic and body-centred cubic are 1,4,2 respectively.
Terbium Atomic and Orbital Properties
Terbium atoms have 65 electrons and the electronic shell structure is [2, 8, 18, 27, 8, 2] with Atomic Term Symbol (Quantum Numbers) 6H15/2.
| Atomic Number | 65 |
| Number of Electrons (with no charge) | 65 |
| Number of Protons | 65 |
| Mass Number | 159 |
| Number of Neutrons | 94 |
| Shell structure (Electrons per energy level) | 2, 8, 18, 27, 8, 2 |
| Electron Configuration | [Xe] 4f9 6s2 |
| Valence Electrons | 4f9 6s2 |
| Valence (Valency) | 3 |
| Main Oxidation States | 3 |
| Oxidation States | 0, 1, 2, 3, 4 |
| Atomic Term Symbol (Quantum Numbers) | 6H15/2 |
Bohr Atomic Model of Terbium - Electrons per energy level
| n | s | p | d | f |
|---|
Ground State Electronic Configuration of Terbium - neutral Terbium atom
Abbreviated electronic configuration of Terbium
The ground state abbreviated electronic configuration of Neutral Terbium atom is [Xe] 4f9 6s2. The portion of Terbium configuration that is equivalent to the noble gas of the preceding period, is abbreviated as [Xe]. 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 4f9 6s2, electrons in the outermost shell that determine the chemical properties of the element.
Unabbreviated electronic configuration of neutral Terbium
Complete ground state electronic configuration for the Terbium atom, Unabbreviated electronic configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f9 6s2
Electrons are filled in atomic orbitals as per the order determined by the Aufbau principle, Pauli Exclusion Principle and Hund’s Rule.
As per the Aufbau principle the electrons will occupy the orbitals having lower energies before occupying higher energy orbitals. According to this principle, electrons are filled in the following order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p…
The Pauli exclusion principle states that a maximum of two electrons, each having opposite spins, can fit in an orbital.
Hund's rule states that every orbital in a given subshell is singly occupied by electrons before a second electron is filled in an orbital.
Atomic Structure of Terbium
Terbium atomic radius is 225 pm, while it's covalent radius is -.
| Atomic Radius Calculated | 225 pm(2.25 Å) |
| Atomic Radius Empirical | 175 pm (1.75 Å) |
| Atomic Volume | 19.336 cm3/mol |
| Covalent Radius | - |
| Van der Waals Radius | - |
| Neutron Cross Section | 23 |
| Neutron Mass Absorption | 0.009 |
Spectral Lines of Terbium - Atomic Spectrum of Terbium
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules.
Spectral lines are the result of interaction between a quantum system and a single photon. A spectral line may be observed either as an emission line or an absorption line.
Spectral lines are highly atom-specific, and can be used to identify the chemical composition of any medium. Several elements, including helium, thallium, and caesium, were discovered by spectroscopic means. They are widely used to determine the physical conditions of stars and other celestial bodies that cannot be analyzed by other means.
Emission spectrum of Terbium
Absorption spectrum of Terbium
Terbium Chemical Properties: Terbium Ionization Energies and electron affinity
The electron affinity of Terbium is 50 kJ/mol.
| Valence | 3 |
| Electronegativity | 1.1 |
| ElectronAffinity | 50 kJ/mol |
Ionization Energy of Terbium
Ionization energy is the amount of energy required to remove an electron from an atom or molecule.in chemistry, this energy is expresed in kilocalories per mole (kcal/mol) or kilojoules per mole (kJ/mol).
Refer to table below for Ionization energies of Terbium
| Ionization energy number | Enthalpy - kJ/mol |
|---|---|
| 1st | 565.8 |
| 2nd | 1110 |
| 3rd | 2114 |
| 4th | 3839 |
Terbium Physical Properties
Refer to below table for Terbium Physical Properties
| Density | 8.219 g/cm3(when liquid at m.p density is $7.65 g/cm3) |
| Molar Volume | 19.336 cm3/mol |
Elastic Properties
| Young Modulus | 56 |
| Shear Modulus | 22 GPa |
| Bulk Modulus | 38.7 GPa |
| Poisson Ratio | 0.26 |
Hardness of Terbium - Tests to Measure of Hardness of Element
| Mohs Hardness | - |
| Vickers Hardness | 863 MPa |
| Brinell Hardness | 677 MPa |
Terbium Electrical Properties
Electrical resistivity measures element's electrical resistance or how strongly it resists electric current.The SI unit of electrical resistivity is the ohm-metre (Ω⋅m). While Electrical conductivity is the reciprocal of electrical resistivity. It represents a element's ability to conduct electric current. The SI unit of electrical conductivity is siemens per metre (S/m).
Terbium is a conductor of electricity. Refer to table below for the Electrical properties of Terbium
| Electrical conductors | Conductor |
| Electrical Conductivity | 830000 S/m |
| Resistivity | 0.0000012 m Ω |
| Superconducting Point | - |
Terbium Heat and Conduction Properties
| Thermal Conductivity | 11 W/(m K) |
| Thermal Expansion | 0.0000103 /K |
Terbium Magnetic Properties
| Magnetic Type | Paramagnetic |
| Curie Point | 222 K |
| Mass Magnetic Susceptibility | 0.0000136 m3/kg |
| Molar Magnetic Susceptibility | 0.000002161385 m3/mol |
| Volume Magnetic Susceptibility | 0.1117784 |
Optical Properties of Terbium
| Refractive Index | - |
Acoustic Properties of Terbium
| Speed of Sound | 2620 m/s |
Terbium Thermal Properties - Enthalpies and thermodynamics
Refer to table below for Thermal properties of Terbium
| Melting Point | 1629 K(1355.85 °C, 2472.530 °F) |
| Boiling Point | 3503 K(3229.85 °C, 5845.730 °F) |
| Critical Temperature | - |
| Superconducting Point | - |
Enthalpies of Terbium
| Heat of Fusion | 10.8 kJ/mol |
| Heat of Vaporization | 295 kJ/mol |
| Heat of Combustion | - |
Terbium Isotopes - Nuclear Properties of Terbium
Terbium has 36 isotopes, with between 136 and 171 nucleons. Terbium has 1 stable naturally occuring isotopes.
Isotopes of Terbium - Naturally occurring stable Isotopes: 159Tb.
| Isotope | Z | N | Isotope Mass | % Abundance | T half | Decay Mode |
|---|---|---|---|---|---|---|
| 136Tb | 65 | 71 | 136 | Synthetic | ||
| 137Tb | 65 | 72 | 137 | Synthetic | ||
| 138Tb | 65 | 73 | 138 | Synthetic | ||
| 139Tb | 65 | 74 | 139 | Synthetic | ||
| 140Tb | 65 | 75 | 140 | Synthetic | ||
| 141Tb | 65 | 76 | 141 | Synthetic | ||
| 142Tb | 65 | 77 | 142 | Synthetic | ||
| 143Tb | 65 | 78 | 143 | Synthetic | ||
| 144Tb | 65 | 79 | 144 | Synthetic | ||
| 145Tb | 65 | 80 | 145 | Synthetic | ||
| 146Tb | 65 | 81 | 146 | Synthetic | ||
| 147Tb | 65 | 82 | 147 | Synthetic | ||
| 148Tb | 65 | 83 | 148 | Synthetic | ||
| 149Tb | 65 | 84 | 149 | Synthetic | ||
| 150Tb | 65 | 85 | 150 | Synthetic | ||
| 151Tb | 65 | 86 | 151 | Synthetic | ||
| 152Tb | 65 | 87 | 152 | Synthetic | ||
| 153Tb | 65 | 88 | 153 | Synthetic | ||
| 154Tb | 65 | 89 | 154 | Synthetic | ||
| 155Tb | 65 | 90 | 155 | Synthetic | ||
| 156Tb | 65 | 91 | 156 | Synthetic | ||
| 157Tb | 65 | 92 | 157 | Synthetic | ||
| 158Tb | 65 | 93 | 158 | Synthetic | ||
| 159Tb | 65 | 94 | 159 | 100% | Stable | |
| 160Tb | 65 | 95 | 160 | Synthetic | ||
| 161Tb | 65 | 96 | 161 | Synthetic | ||
| 162Tb | 65 | 97 | 162 | Synthetic | ||
| 163Tb | 65 | 98 | 163 | Synthetic | ||
| 164Tb | 65 | 99 | 164 | Synthetic | ||
| 165Tb | 65 | 100 | 165 | Synthetic | ||
| 166Tb | 65 | 101 | 166 | Synthetic | ||
| 167Tb | 65 | 102 | 167 | Synthetic | ||
| 168Tb | 65 | 103 | 168 | Synthetic | ||
| 169Tb | 65 | 104 | 169 | Synthetic | ||
| 170Tb | 65 | 105 | 170 | Synthetic | ||
| 171Tb | 65 | 106 | 171 | Synthetic |
Regulatory and Health - Health and Safety Parameters and Guidelines
The United States Department of Transportation (DOT) identifies hazard class of all dangerous elements/goods/commodities either by its class (or division) number or name. The DOT has divided these materials into nine different categories, known as Hazard Classes.
NFPA 704 is a Standard System for the Identification of the Hazards of Materials for Emergency Response. NFPA is a standard maintained by the US based National Fire Protection Association.
The health (blue), flammability (red), and reactivity (yellow) rating all use a numbering scale ranging from 0 to 4. A value of zero means that the element poses no hazard; a rating of four indicates extreme danger.
| NFPA Fire Rating | N/A | N/A |
| NFPA Health Rating | N/A | N/A |
| NFPA Reactivity Rating | N/A | N/A |
| NFPA Hazards | N/A |
| Autoignition Point | - |
| Flashpoint | - |
Database Search
List of unique identifiers to search the element in various chemical registry databases
| Database | Identifier number |
|---|---|
| CAS Number - Chemical Abstracts Service (CAS) | CAS7440-27-9 |
| RTECS Number | - |
| CID Number | CID23958 |
| Gmelin Number | - |
| NSC Number | - |
Compare Terbium with other elements
Compare Terbium with Group , Period 6 and Lanthanide elements of the periodic table.
Compare Terbium with all Group elements
Compare Terbium with all Period 6 elements
Compare Terbium with all Lanthanide elements
Frequently Asked Questions (FAQ)
Find the answers to the most frequently asked questions about Terbium