Astatine is a very rare radioactive chemical element with the chemical symbol At and atomic number 85. It occurs on Earth as the decay product of various heavier elements. All its isotopes are short-lived; the most stable is astatine-210, with a half-life of 8.1 hours.
Read key information and facts about element Astatine
|Group in Periodic Table||17|
|Group Name||fluorine family|
|Period in Periodic Table||6|
|Block in Periodic Table||p-block|
|Electronic Configuration||[Xe] 4f14 5d10 6s2 6p5|
|Melting Point||302 °C|
|Electronic Shell Structure||[2, 8, 18, 32, 18, 7]|
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 85 to find Astatine 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 Astatine on periodic table look for cross section of group 17 and period 6 in the modern periodic table.
The element Astatine was discovered by Dale R. Corson in year 1940 in United States . Astatine derived its name from the Greek astatos, 'unstable'
The table below shows the abundance of Astatine in Universe, Sun, Meteorites, Earth's Crust, Oceans and Human Body.
|Ppb by weight (1ppb =10^-7 %)|
|Abundance in Universe||N/A|
|Abundance in Sun||N/A|
|Abundance in Meteorites||None|
|Abundance in Earth's Crust||None|
|Abundance in Oceans||None|
|Abundance in Humans||None|
The solid state structure of Astatine is Face Centered Cubic.
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.
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)
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||N/A|
|Space Group Number||N/A|
|Crystal Structure||Face Centered Cubic|
Astatine atoms have 85 electrons and the electronic shell structure is [2, 8, 18, 32, 18, 7] with Atomic Term Symbol (Quantum Numbers) 2P3/2.
|Number of Electrons (with no charge)||85|
|Number of Protons||85|
|Number of Neutrons||125|
|Shell structure (Electrons per energy level)||[2, 8, 18, 32, 18, 7]|
|Electron Configuration||[Xe] 4f14 5d10 6s2 6p5|
|Valence Electrons||6s2 6p5|
|Atomic Term Symbol (Quantum Numbers)||2P3/2|
Shell Structure of Astatine - Electrons per energy level
The ground state electronic configuration of Neutral Astatine atom is [Xe] 4f14 5d10 6s2 6p5. The portion of Astatine 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 4f14 5d10 6s2 6p5, electrons in the outermost shell that determine the chemical properties of the element.
Complete ground state electronic configuration for the Astatine atom, Unabbreviated electronic configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p5
Astatine atomic radius is 127 pm, while it's covalent radius is N/A.
127 pm (1.27 Å)
|Atomic Volume||N/A cm3|
|Van der Waals Radius||N/A|
|Neutron Cross Section||N/A σa/barns|
The electron affinity of Astatine is 270.1 kJ/mol
Refer to table below for Ionization energies of Astatine
|Ionization energy number||Enthalpy - kJ/mol|
Refer to below table for Astatine Physical Properties
|Molar Volume||N/A cm3|
Astatine is N/A of electricity. Refer to table below for the Electrical properties of Astatine
|Thermal Conductivity||2 W/(m K)|
|Mass Magnetic Susceptibility||N/A|
|Molar Magnetic Susceptibility||N/A|
|Volume Magnetic Susceptibility||N/A|
|Speed of Sound||N/A|
Refer to table below for Thermal properties of Astatine
|Melting Point||575 K (302 °C)|
|Boiling Point||N/A (N/A)|
|Heat of Fusion||6 kJ/mol|
|Heat of Vaporization||40 kJ/mol|
|Heat of Combustion||N/A|
Isotopes of rhodium. Naturally occurring Astatine has 1 stable isotope - None.
|Isotope||Isotope Mass||% Abundance||T half||Decay Mode|
|DOT Hazard Class||N/A|
|NFPA Fire Rating||N/A|
|NFPA Health Rating||N/A|
|NFPA Reactivity Rating||N/A|
List of unique identifiers to search the element in various chemical registry databases
|CAS Number - Chemical Abstracts Service (CAS)||CAS7440-68-8|
|Alkali Metals||Alkaline Earth Metals|
|Transition Metals||Post-Transition Metals|