Tl Thallium
Element Information, Facts, Properties, Trends, Uses, Comparison with other elements
Thallium is a chemical element with symbol Tl and atomic number 81. This soft gray Post Transition Metal is not found free in nature. When isolated, it resembles tin, but discolors when exposed to air.
It belongs to group 13 of the periodic table having trivial name triels, icosagens.
Thallium Facts
Read key information and facts about element Thallium
| Name | Thallium |
| Atomic Number | 81 |
| Atomic Symbol | Tl |
| Atomic Weight | 204.3833 |
| Phase | Solid |
| Color | Silver |
| Appearance | silvery white |
| Classification | Post Transition Metal |
| Group in Periodic Table | 13 |
| Group Name | boron family |
| Period in Periodic Table | period 6 |
| Block in Periodic Table | p -block |
| Electronic Configuration | [Xe] 4f14 5d10 6s2 6p1 |
| Electronic Shell Structure (Electrons per shell) | 2, 8, 18, 32, 18, 3 |
| Melting Point | 577 K |
| Boiling Point | 1746 K |
| CAS Number | CAS7440-28-0 |
How to Locate Thallium 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 81 to find Thallium 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 Thallium on periodic table look for cross section of group 13 and period 6 in the modern periodic table.
Thallium History
The element Thallium was discovered by W. Crookes in year 1861 in United Kingdom. Thallium was first isolated by C.-A. Lamy in 1862. Thallium derived its name from the Greek thallos, 'green twig'.
Shortly after the discovery of rubidium, Crookes found a new green line in a selenium sample; later that year, Lamy found the element to be metallic.
Thallium Presence: Abundance in Nature and Around Us
The table below shows the abundance of Thallium 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 | 0.003 |
| Abundance in Sun | 1 | 0.01 |
| Abundance in Meteorites | 80 | 6 |
| Abundance in Earth's Crust | 530 | 50 |
| Abundance in Oceans | 0.001 | 0.000030 |
| Abundance in Humans | - | - |
Crystal Structure of Thallium
The solid state structure of Thallium 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 |
|---|---|---|
| 345.66 pm | 345.66 pm | 552.48 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.
Thallium Atomic and Orbital Properties
Thallium atoms have 81 electrons and the electronic shell structure is [2, 8, 18, 32, 18, 3] with Atomic Term Symbol (Quantum Numbers) 2P1/2.
| Atomic Number | 81 |
| Number of Electrons (with no charge) | 81 |
| Number of Protons | 81 |
| Mass Number | 204 |
| Number of Neutrons | 123 |
| Shell structure (Electrons per energy level) | 2, 8, 18, 32, 18, 3 |
| Electron Configuration | [Xe] 4f14 5d10 6s2 6p1 |
| Valence Electrons | 6s2 6p1 |
| Valence (Valency) | 3 |
| Main Oxidation States | 1, 3 |
| Oxidation States | -5, -2, -1, 1, 2, 3 |
| Atomic Term Symbol (Quantum Numbers) | 2P1/2 |
Bohr Atomic Model of Thallium - Electrons per energy level
| n | s | p | d | f |
|---|
Ground State Electronic Configuration of Thallium - neutral Thallium atom
Abbreviated electronic configuration of Thallium
The ground state abbreviated electronic configuration of Neutral Thallium atom is [Xe] 4f14 5d10 6s2 6p1. The portion of Thallium 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 6s2 6p1, electrons in the outermost shell that determine the chemical properties of the element.
Unabbreviated electronic configuration of neutral Thallium
Complete ground state electronic configuration for the Thallium atom, Unabbreviated electronic configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p1
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 Thallium
Thallium atomic radius is 156 pm, while it's covalent radius is 148 pm.
| Atomic Radius Calculated | 156 pm (1.56 Å) |
| Atomic Radius Empirical | 190 pm (1.9 Å) |
| Atomic Volume | 17.24 cm3/mol |
| Covalent Radius | 148 pm (1.48 Å) |
| Van der Waals Radius | 196 pm |
| Neutron Cross Section | 3.4 |
| Neutron Mass Absorption | 0.0006 |
Atomic Spectrum of Thallium
Thallium Chemical Properties: Thallium Ionization Energies and electron affinity
The electron affinity of Thallium is 19.2 kJ/mol.
| Valence | 3 |
| Electronegativity | 1.62 |
| ElectronAffinity | 19.2 kJ/mol |
Ionization Energy of Thallium
Refer to table below for Ionization energies of Thallium
| Ionization energy number | Enthalpy - kJ/mol |
|---|---|
| 1st | 589.4 |
| 2nd | 1971 |
| 3rd | 2878 |
Thallium Physical Properties
Refer to below table for Thallium Physical Properties
| Density | 11.85 g/cm3(when liquid at m.p density is $11.22 g/cm3) |
| Molar Volume | 17.24 cm3/mol |
Elastic Properties
| Young Modulus | 8 |
| Shear Modulus | 2.8 GPa |
| Bulk Modulus | 43 GPa |
| Poisson Ratio | 0.45 |
Hardness of Thallium - Tests to Measure of Hardness of Element
| Mohs Hardness | 1.2 MPa |
| Vickers Hardness | - |
| Brinell Hardness | 26.4 MPa |
Thallium Electrical Properties
Thallium is Conductor of electricity. Refer to table below for the Electrical properties ofThallium
| Electrical Conductivity | 6700000 S/m |
| Resistivity | 1.5e-7 m Ω |
| Superconducting Point | 2.38 |
Thallium Heat and Conduction Properties
| Thermal Conductivity | 46 W/(m K) |
| Thermal Expansion | 0.0000299 /K |
Thallium Magnetic Properties
| Magnetic Type | Diamagnetic |
| Curie Point | - |
| Mass Magnetic Susceptibility | -3e-9 m3/kg |
| Molar Magnetic Susceptibility | -6.13e-10 m3/mol |
| Volume Magnetic Susceptibility | -0.0000356 |
Optical Properties of Thallium
| Refractive Index | - |
Acoustic Properties of Thallium
| Speed of Sound | 818 m/s |
Thallium Thermal Properties - Enthalpies and thermodynamics
Refer to table below for Thermal properties of Thallium
| Melting Point | 577 K (303.85°C, 578.9300000000001 °F) |
| Boiling Point | 1746 K (1472.85°C, 2683.13 °F) |
| Critical Temperature | - |
| Superconducting Point | 2.38 |
Enthalpies of Thallium
| Heat of Fusion | 4.2 kJ/mol |
| Heat of Vaporization | 165 kJ/mol |
| Heat of Combustion | - |
Thallium Isotopes - Nuclear Properties of Thallium
Thallium has 37 isotopes, with between 176 and 212 nucleons. Thallium has 2 stable naturally occuring isotopes.
Isotopes of Thallium - Naturally occurring stable Isotopes: 203Tl, 205Tl.
| Isotope | Z | N | Isotope Mass | % Abundance | T half | Decay Mode |
|---|---|---|---|---|---|---|
| 176Tl | 81 | 95 | 176 | Synthetic | ||
| 177Tl | 81 | 96 | 177 | Synthetic | ||
| 178Tl | 81 | 97 | 178 | Synthetic | ||
| 179Tl | 81 | 98 | 179 | Synthetic | ||
| 180Tl | 81 | 99 | 180 | Synthetic | ||
| 181Tl | 81 | 100 | 181 | Synthetic | ||
| 182Tl | 81 | 101 | 182 | Synthetic | ||
| 183Tl | 81 | 102 | 183 | Synthetic | ||
| 184Tl | 81 | 103 | 184 | Synthetic | ||
| 185Tl | 81 | 104 | 185 | Synthetic | ||
| 186Tl | 81 | 105 | 186 | Synthetic | ||
| 187Tl | 81 | 106 | 187 | Synthetic | ||
| 188Tl | 81 | 107 | 188 | Synthetic | ||
| 189Tl | 81 | 108 | 189 | Synthetic | ||
| 190Tl | 81 | 109 | 190 | Synthetic | ||
| 191Tl | 81 | 110 | 191 | Synthetic | ||
| 192Tl | 81 | 111 | 192 | Synthetic | ||
| 193Tl | 81 | 112 | 193 | Synthetic | ||
| 194Tl | 81 | 113 | 194 | Synthetic | ||
| 195Tl | 81 | 114 | 195 | Synthetic | ||
| 196Tl | 81 | 115 | 196 | Synthetic | ||
| 197Tl | 81 | 116 | 197 | Synthetic | ||
| 198Tl | 81 | 117 | 198 | Synthetic | ||
| 199Tl | 81 | 118 | 199 | Synthetic | ||
| 200Tl | 81 | 119 | 200 | Synthetic | ||
| 201Tl | 81 | 120 | 201 | Synthetic | ||
| 202Tl | 81 | 121 | 202 | Synthetic | ||
| 203Tl | 81 | 122 | 203 | 29.524% | Stable | N/A |
| 204Tl | 81 | 123 | 204 | Synthetic | Stable | |
| 205Tl | 81 | 124 | 205 | 70.476% | Stable | N/A |
| 206Tl | 81 | 125 | 206 | Synthetic | ||
| 207Tl | 81 | 126 | 207 | Synthetic | ||
| 208Tl | 81 | 127 | 208 | Synthetic | ||
| 209Tl | 81 | 128 | 209 | Synthetic | ||
| 210Tl | 81 | 129 | 210 | Synthetic | ||
| 211Tl | 81 | 130 | 211 | Synthetic | ||
| 212Tl | 81 | 131 | 212 | Synthetic |
Regulatory and Health - Health and Safety Parameters and Guidelines
Database Search
List of unique identifiers to search the element in various chemical registry databases
| Database | Identifier number |
|---|---|
| CAS Number - Chemical Abstracts Service (CAS) | CAS7440-28-0 |
| RTECS Number | RTECSXG3425000 |
| CID Number | CID5359464 |
| Gmelin Number | - |
| NSC Number | - |
Compare Thallium with other elements
Compare Thallium with all Group 13 elements
Compare Thallium with all Period 6 elements
Compare Thallium with all Post Transition Metal elements
FAQs
What is the electronic configuration of Thallium?
The electronic configuration of Thallium is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p1.
What is the abbreviated electronic configuration of Thallium?
The abbreviated electronic configuration of Thallium is [Xe] 4f14 5d10 6s2 6p1. To form abbreviated notation of electronic configuration, the completely filled subshells are replaced by the noble gas of the preceding period in square brackets.
What is the symbol of Thallium?
Symbol of Thallium is Tl. Thallium is a chemical element with symbol Tl and atomic number 81.
What is the position of Thallium in the Periodic Table?
Thallium is a chemical element with the symbol Tl and atomic number 81. Thallium is the 81 element on the periodic table. It is located in group 13 and period 6 in the modern periodic table.
What is the atomic number of Thallium?
The atomic number of Thallium is 81.
What is the color of Thallium?
Thallium is of Silver color.
Who discovered Thallium?
The element Thallium was discovered by W. Crookes in year 1861 in United Kingdom. Thallium was first isolated by C.-A. Lamy in 1862.
How many valence electrons does a Thallium atom have?
Thallium has 3 valence electrons. Thallium has 81 electrons out of which 3 valence electrons are present in the 6s2 6p1 outer orbitals of atom.
What is the melting Point of Thallium?
Melting Point of Thallium is 577 K.
What is the boiling Point of Thallium?
Boiling Point of Thallium is 1746 K.
What is the melting Point of Thallium in Kelvin?
Melting Point of Thallium in Kelvin is 577 K.
What is the boiling Point of Thallium in Kelvin?
Boiling Point of Thallium in Kelvin is 1746 K.
What is the electronic configuration of Thallium 81?
The electronic configuration of Thallium will be 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p1.
How do you write the electron configuration for Thallium?
The electronic configuration of Thallium will be 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p1.