Promethium, originally prometheum, is a chemical element with the symbol Pm and atomic number 61. All of its isotopes are radioactive; it is one of only two such elements that are followed in the periodic table by elements with stable forms, a distinction shared with technetium. Chemically, promethium is a lanthanide, which forms salts when combined with other elements.
Read key information and facts about element Promethium
|Group in Periodic Table||N/A|
|Period in Periodic Table||6|
|Block in Periodic Table||f-block|
|Electronic Configuration||[Xe] 4f5 6s2|
|Melting Point||1.1×103 °C|
|Boiling Point||3×103 °C|
|Electronic Shell Structure||[2, 8, 18, 23, 8, 2]|
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 61 to find Promethium 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 Promethium on periodic table look for cross section of group N/A and period 6 in the modern periodic table.
The element Promethium was discovered by Chien Shiung Wu in year 1945 in United States . Promethium derived its name from Prometheus of Greek mythology who stole fire from the Gods and gave it to humans
The table below shows the abundance of Promethium 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||None|
|Abundance in Meteorites||None|
|Abundance in Earth's Crust||None|
|Abundance in Oceans||None|
|Abundance in Humans||None|
The solid state structure of Promethium 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.
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||Simple Hexagonal|
Promethium atoms have 61 electrons and the electronic shell structure is [2, 8, 18, 23, 8, 2] with Atomic Term Symbol (Quantum Numbers) 6H5/2.
|Number of Electrons (with no charge)||61|
|Number of Protons||61|
|Number of Neutrons||84|
|Shell structure (Electrons per energy level)||[2, 8, 18, 23, 8, 2]|
|Electron Configuration||[Xe] 4f5 6s2|
|Valence Electrons||4f5 6s2|
|Atomic Term Symbol (Quantum Numbers)||6H5/2|
Shell Structure of Promethium - Electrons per energy level
The ground state electronic configuration of Neutral Promethium atom is [Xe] 4f5 6s2. The portion of Promethium 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 4f5 6s2, electrons in the outermost shell that determine the chemical properties of the element.
Complete ground state electronic configuration for the Promethium atom, Unabbreviated electronic configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f5 6s2
Promethium atomic radius is 205 pm, while it's covalent radius is N/A.
205 pm (2.05 Å)
|Atomic Volume||19.9614537445 cm3|
|Van der Waals Radius||N/A|
|Neutron Cross Section||8×103 σa/barns|
The electron affinity of Promethium is 50 kJ/mol
Refer to table below for Ionization energies of Promethium
|Ionization energy number||Enthalpy - kJ/mol|
Refer to below table for Promethium Physical Properties
|Molar Volume||19.9614537445 cm3|
|Young Modulus||46 GPa|
|Shear Modulus||18 GPa|
|Bulk Modulus||33 GPa|
Promethium is Conductor of electricity. Refer to table below for the Electrical properties of Promethium
|Electrical Conductivity||1.3×106 S/m|
|Resistivity||7.5×10-7 m Ω|
|Thermal Conductivity||15 W/(m K)|
|Thermal Expansion||0.000011 K-1|
|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 Promethium
|Melting Point||1373 K (1.1×103 °C)|
|Boiling Point||3273 K (3×103 °C)|
|Heat of Fusion||7.7 kJ/mol|
|Heat of Vaporization||290 kJ/mol|
|Heat of Combustion||N/A|
Isotopes of rhodium. Naturally occurring Promethium 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)||CAS7440-12-2|
|Alkali Metals||Alkaline Earth Metals|
|Transition Metals||Post-Transition Metals|