Promethium

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Promethium

Promethium is a chemical element

Chemical element

A chemical element is a type of atom that is distinguished by its atomic number; that is, by the number of protons in its atomic nucleus. The term is also used to refer to a pure chemical Chemical substance composed of atoms with the same number of protons....
with the symbol Pm and atomic number

Atomic number

In chemistry and physics, the atomic number is the number of protons found in the atomic nucleus of an atom. It is conventionally represented by the symbol Z....
61. It is notable for being the only other exclusively radioactive element besides technetium

Technetium

Technetium is the lightest chemical element with no stable isotope. It is a synthetic element with the atomic number 43 and is given the symbol Tc....
which is followed by chemical elements that have stable isotopes.
ethium's longest lived isotope ¹⁴⁵Pm is a soft beta

Beta particle

Beta particles are high-energy, high-speed electrons or positrons emitted by certain types of radioactive Atomic nucleus such as potassium-40. The beta particles emitted are a form of ionizing radiation also known as beta rays....
emitter with a half-life of 17.7 years. It does not emit gamma ray

Gamma ray

Gamma rays are a form of electromagnetic radiation produced by atom particle interactions, such as electron-positron annihilation or radioactive decay....
s, but beta particles impinging on elements of high atomic numbers can generate X-ray

X-ray

X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 10 to 0.01 nanometers, corresponding to frequency in the range 30 Hertz to 30 Hertz and energies in the range 120 Electron volt to 120 keV....
s, and a sample of ¹⁴⁵Pm does produce some such soft X-ray radiation in addition to beta particles.

Pure promethium exists in two allotropic forms, and its chemistry is similar to other lanthanide

Lanthanide

According to the IUPAC terminology, the lanthanoid series comprises the fifteen chemical elements with atomic numbers 57 through 71, from lanthanum to lutetium....
s.

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Encyclopedia

Promethium is a chemical element

Chemical element

Atomic number

Technetium

Characteristics

Promethium's longest lived isotope ¹⁴⁵Pm is a soft beta

Beta particle

Gamma ray

X-ray

Lanthanide

According to the IUPAC terminology, the lanthanoid series comprises the fifteen chemical elements with atomic numbers 57 through 71, from lanthanum to lutetium....
s. Promethium salts luminesce in the dark with a pale blue or greenish glow, due to their high radioactivity. Promethium can be found in traces in some uranium

Uranium

Uranium is a silvery-gray metallic chemical element in the actinide series of the periodic table that has the chemical symbol U and atomic number 92....
ores, as a fission product. Newly made promethium is also seen in the spectra of some stars.

Applications

Uses for promethium include:

As a beta radiation source for thickness gauges.
As a light source for signals that require reliable, independent operation (using phosphor
Phosphor

A phosphor is a substance that exhibits the optical phenomenon of phosphorescence .Phosphors are transition metal compounds or rare earth element compounds of various types....
to absorb the beta radiation and produce light).
In a nuclear battery in which cells convert the beta emissions into electric current, yielding a useful life of about five years, using Pm-147.
Promethium(III) chloride (PmCl₃) mixed with zinc sulfide
Zinc sulfide

Zinc sulfide is a chemical compound with the chemical formula ZincSulfur. Zinc sulfide is a white- to yellow-colored powder or crystal. It is typically encountered in the more stable cubic form, known also as zinc blende or sphalerite....
(Zn
Zinc

Zinc is a metallic chemical element with the symbol Zn and atomic number 30. It is a first-row transition metal of the group 12 element of the periodic table....
S
Sulfur

Sulfur or sulphur is the chemical element that has the atomic number 16. It is denoted with the symbol S. It is an abundant Valence non-metal....
) was used for a time as a major luminous paint for watches after radium
Radium

Radium is a radioactive chemical element which has the symbol Ra and atomic number 88. Its appearance is almost pure white, but it readily oxidizes on exposure to air, turning black....
was discontinued. This mixture is still occasionally used for some luminous paint applications (though most such uses with radioactive materials have switched to tritium
Tritium

Tritium is a radioactive isotope of hydrogen. The atomic nucleus of tritium contains one proton and two neutrons, whereas the nucleus of Hydrogen atom contains one proton and no neutrons....
for safety reasons).
Promethium has possible future uses in portable X-ray sources, and as auxiliary heat or power sources for space probes and satellites (although the alpha emitter plutonium-238
Plutonium-238

Plutonium-238, is a radioactive isotope of plutonium with a half-life of 87.7 years and is a very powerful alpha emitter. Because of its high level of alpha activity, it is used for radioisotope thermoelectric generators and radioisotope heater units....
has become standard for most space-exploration related uses – see Radioisotope thermoelectric generators).

History

The existence of promethium was first predicted by Bohuslav Brauner

Bohuslav Brauner

Bohuslav Brauner was a Czechs chemist.Brauner was a student of Robert Bunsen at the University of Heidelberg and later of Henry Roscoe at the University of Manchester....
in 1902; this prediction was supported in 1914 by Henry Moseley

Henry Moseley

Henry Gwyn Jeffreys Moseley was an England physics. His main contributions to science were the quantitative justification of the previously empirical concept of atomic number, and Moseley's law....
who, having discovered that atomic number

Atomic number

In chemistry and physics, the atomic number is the number of protons found in the atomic nucleus of an atom. It is conventionally represented by the symbol Z....
was an experimentally measurable property of elements, found that no known element had atomic number 61. Several groups claimed to have produced the element, but they could not confirm their discoveries because of the difficulty of separating promethium from other elements. Promethium was first produced and proved to exist at Oak Ridge National Laboratory

Oak Ridge National Laboratory

Oak Ridge National Laboratory is a multiprogram science and technology national laboratory managed for the United States Department of Energy by UT-Battelle....
(ORNL) in 1945 by Jacob A. Marinsky

Jacob A. Marinsky

Jacob Akiba Marinsky was a chemist who was the co-discoverer of the element promethium.Marinsky was born in Buffalo, New York, and attended the University at Buffalo, The State University of New York, entering at age 16 and receiving a bachelor's degree in chemistry in 1939....
, Lawrence E. Glendenin

Lawrence E. Glendenin

Lawrence Elgin Glendenin was an United States chemist. He was one of the discoverers of the chemical element promethium.Glendenin was born in Bay City, Michigan in 1918 and attended the University of Chicago, graduating in 1941....
and Charles D. Coryell

Charles D. Coryell

Charles DuBois Coryell was an United States chemist who was one of the discoverers of the chemical element promethium.Coryell earned a Ph.D at California Institute of Technology in 1935....
by separation and analysis of the fission products of uranium

Uranium

Uranium is a silvery-gray metallic chemical element in the actinide series of the periodic table that has the chemical symbol U and atomic number 92....
fuel irradiated in the Graphite Reactor

X-10 Graphite Reactor

The X-10 Graphite Reactor at Oak Ridge National Laboratory in Oak Ridge, Tennessee, formerly known as the Clinton Pile and X-10 Pile, was the world's second artificial nuclear reactor and was the first reactor designed and built for continuous operation....
; however, being too busy with defense-related research during World War II

World War II

World War II, or the Second World War , was a global military conflict which involved a Participants in World War II, including all of the great powers, organised into two opposing military alliances: the Allies of World War II and the Axis powers....
, they did not announce their discovery until 1947. The name promethium is derived from Prometheus

Prometheus

In Greek mythology, Prometheus is a Titan known for his wily intelligence, who stole fire from Zeus and gave it to human beings for their use....
, the Titan, in Greek mythology

Greek mythology

Greek mythology is the body of myths and legends belonging to the Ancient Greece concerning their List of Greek mythological figures#Immortals and Greek hero cult, Cosmology#Metaphysical cosmology, and the origins and significance of their own cult and ritual practices....
, who stole the fire from Mount Olympus and brought it down to mankind. The name was suggested by Grace Mary Coryell, Charles Coryell's wife, who felt that they were stealing fire from the gods.

In 1963, ion-exchange methods were used at ORNL to prepare about ten grams of promethium from nuclear reactor fuel processing wastes.

Today, promethium is still recovered from the byproducts of uranium fission; it can also be produced by bombarding ¹⁴⁶Nd with neutron

Neutron

The neutron is a subatomic particle with no net electric charge and a mass slightly larger than that of a proton.Neutrons are usually found in atomic nucleus....
s, turning it into ¹⁴⁷Nd which decays into ¹⁴⁷Pm

Promethium-147

Occurrence

Promethium can be formed in nature as a product of spontaneous fission

Spontaneous fission

Spontaneous fission is a form of radioactive decay characteristic of very heavy isotopes, and is theoretically possible for any atomic nucleus whose mass is greater than or equal to 100 atomic mass unit ....
of uranium-238

Uranium-238

Uranium-238 , is the most common Isotopes of uranium of uranium found in nature. When hit by a neutron, it becomes uranium-239 , an unstable isotope which radioactive decay into neptunium-239 , which then itself decays, with a half-life of 2.355 days, into plutonium-239 ....
and alpha decay

Alpha decay

Alpha decay is a type of radioactivity decay in which an atomic nucleus emits an alpha particle and transforms into an atom with a mass number 4 less and atomic number 2 less....
of europium

Europium

Europium is a chemical element with the symbol Eu and atomic number 63. It was named after the continent Europe.Characteristics ...
-151. Only trace amounts can be found in naturally occurring ores: a sample of pitchblende has been found to contain promethium at a concentration of four parts per quintillion (10¹⁸) by mass. It was calculated that the equilibrium mass of promethium in the earth's crust is about 560 g due to uranium fission and about 12 g due to the recently observed alpha decay of europium-151

Promethium has also been identified in the spectrum of the star HR 465

HR 465

HR 465 is an Alpha2 Canum Venaticorum variable variable star in the constellation Andromeda . Its brightness fluctuates between 6.27 mag and 6.41 mag....
in Andromeda

Andromeda (constellation)

Andromeda is a constellation in the northern sky. It is named after Andromeda , the princess of a mythological kingdom Ethiopia in Greek mythology....
, and possibly HD 101065 (Przybylski's star

Przybylski's star

Przybylski's Star is a peculiar star that is located about 410 light years from the Sun in the constellation Centaurus.In 1961, the Polish-Australian astronomer Antoni Przybylski discovered that this star had a peculiar spectrum that would not fit into the standard framework for stellar classification....
) and HD 965.

Compounds

Promethium compounds include:

Chlorides

PmCl₃

Bromides

PmBr₃

Oxides

Pm₂O₃
Promethium(III) oxide

Promethium oxide is a promethium compound with the formula Pm2O3. It is the most common form of promethium....

Isotopes

Thirty-six radioisotopes of promethium have been characterized, with the most stable being ¹⁴⁵Pm with a half-life

Half-life

The half-life of a quantity whose value decreases with time is the interval required for the quantity to decay to half of its initial value. The concept originated in describing how long it takes atoms to undergo radioactive decay but also applies in a wide variety of other situations....
of 17.7 years, ¹⁴⁶Pm with a half-life of 5.53 years, and ¹⁴⁷Pm

Promethium-147

Promethium-147 is an isotope of promethium with a half-life of 2.62 years. It is the promethium isotope most easily producible, because it is a fission product from nuclear reactors....
with a half-life of 2.6234 years. All of the remaining radioactive isotopes have half-lives that are less than 364 days, and the majority of these have half lives that are less than 27 seconds. This element also has 11 meta states with the most stable being ¹⁴⁸Pm^m (T_½ 41.29 days), ¹⁵²Pm^m2 (T_½ 13.8 minutes) and ¹⁵²Pm^m (T_½ 7.52 minutes).

The isotopes of promethium range in atomic weight

Atomic weight

Atomic weight is a Dimensionless quantity physical quantity, the ratio of the average mass of atoms of an chemical element to 1/12 of the mass of an atom of carbon-12....
from 127.9482600 u

Atomic mass unit

The unified atomic mass unit , or dalton or, sometimes, universal mass unit, is a Units of measurement of mass used to express atomic weight and molecular masses....
(¹²⁸Pm) to 162.9535200 u (¹⁶³Pm). The primary decay mode before the longest-lived isotope, ¹⁴⁵Pm, is electron capture

Electron capture

Electron capture is a decay mode for isotopes that will occur when there are too many protons in the atomic nucleus of an atom and insufficient energy to emit a positron; however, it continues to be a viable decay mode for radioactive isotopes that can decay by positron emission....
, and the primary mode after is beta minus decay. The primary decay product

Decay product

In nuclear physics, a decay product, also known as a daughter product, daughter isotope or daughter nuclide, is a nuclide resulting from the radioactive decay of a parent isotope or precursor nuclide....
s before ¹⁴⁵Pm are neodymium

Neodymium

Neodymium is a chemical element with the symbol Nd and atomic number 60....
(Nd) isotopes and the primary products after are samarium

Samarium

Samarium is a chemical element with the symbol Sm and atomic number 62....
(Sm) isotopes.

Stability of promethium isotopes

Along with technetium

Technetium

Technetium is the lightest chemical element with no stable isotope. It is a synthetic element with the atomic number 43 and is given the symbol Tc....
, promethium is one of only two elements with atomic number less than 83 that have only unstable isotopes, which is a rarely occurring effect

Technetium

Technetium is the lightest chemical element with no stable isotope. It is a synthetic element with the atomic number 43 and is given the symbol Tc....
of the liquid drop model and stabilities of neighbor element isotopes.

Precautions

Promethium must be handled with great care because of its high radioactivity. In particular, promethium can emit X-ray

X-ray

Beta decay

In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted. In the case of electron emission, it is referred to as beta minus , while in the case of a positron emission as beta plus ....
. Its half-life is less than that of plutonium

Plutonium

Plutonium is a rare transuranic radioactive chemical element. It is an actinide metal of silvery-white appearance that tarnishes when exposed to air, forming a dull coating when plutonium oxide....
-239 by a factor of about 1350, and its biological toxicity is correspondingly higher. Promethium has no biological role.

Promethium

Characteristics

Applications

History

Occurrence

Compounds

Isotopes

Stability of promethium isotopes

Precautions

External links