Promethium metal

General

Promethium (by Prometheus, a Greek mythological titan) is a chemical element with the elementary symbol Pm and the ordinal number 61. In the periodic table it is in the group of lanthanides and thus also belongs to the metals of the rare earths.
All promethium isotopes are radioactive, meaning that all nuclei containing 61 protons are unstable and decay. Promethium and the lighter technetium (43) are the only elements of lower atomic number than lead (82) that possess this property.
The first discovery was published by the Italian scientists Luigi Rolla and Lorenzo Fernandes from Florence. After separation of a Didym nitrate concentrate by fractional crystallization from the Brazilian mineral monazite, which consists of 70% dysprosium and neodymium and 30% of the other lanthanides, they received a solution containing mainly samarium. This solution gave X-ray spectra, which they interpreted as samarium and element 61. They named the element 61 in honor of their city Florentium. The results were published in the year 1926, but the scientists claimed that the experiments were conducted in the year 1924.
In the same year, 1926, Smith Hopkins and Len Yntema at the University of Illinois in Urbana-Champaign published the discovery of the element 61. They named it after the University of Illinium.
Neither discovery could be verified. Several groups claimed to have created the element, but they could not confirm their findings because of the difficulty in separating promethium from the other elements.

Recovery

There is no exact knowledge of seperation of promethium.

Promethium in the periodic table

Features

Promethium was discovered by 1945 in the Oak Ridge National Laboratory (Tennessee, USA) by Jacob A. Marinsky, Lawrence E. Glendenin and Charles D. Coryell as a fission product of uranium. Since they were heavily involved in military research during World War II their discovery first released 1947. The name Promethium they chose in reference to the Greek Titan Prometheus, who brought the people the fire and thus aroused the wrath of the gods. This was intended as a warning to humanity, which at that time began with the nuclear arms race. The name was suggested by Grace Mary Coryell, Charles Coryell's wife.
In the year 1963, ion exchange methods were used in ORNL to obtain about 10 grams of promethium from the fuel wastes of nuclear reactors. For the first time, Fritz Weigel was able to produce metallic promethium by heating promethium (III) fluoride (PmF1963) with lithium in the tantalum crucible ,
In nature, promethium is mostly found as a product of the spontaneous fission of uranium as well as alpha decay of the europium isotope 151Eu. It is found in traces in pitchblende in a concentration of (4 ± 1) · 10−15 grams of 147 μm per kg. The regular occurrence of promethium in the earth's crust is about 560 g due to uranium fission and about 12 g due to alpha decay of 151Eu. Promethium was also detected in the emission spectrum of the star GY Andromedae; and possibly in HD 101065 (Przybylski's star) and HD 965.
Since the isotope 147Pm can be obtained artificially as a fission product in weighable quantities, it is possible to investigate the properties quite well. As a metal, it is a typical representative of lanthanides. The silvery-white, relatively soft metal is oxidized quite rapidly in the air and reacts slowly with water.
Promethium only occurs in its compounds in the +3 oxidation state ([Xe] 4f4). It releases the two 6s electrons and one 4f electron. The solutions are purple-tinged pink in color. Among other things, it forms a sparingly soluble fluoride, oxalate and carbonate. Promethium (III) oxide (Pm2O3) has three different modifications: a hexagonal A shape (violet brown), a monoclinic B shape (violet pink) and a cubic C shape (coral red). The melting point is 2130 ° C
All halides from fluorine to iodine are known for the oxidation state + 3.
Promethium (III) fluoride (PmF3) is poorly soluble in water; it is obtained from a nitric acid Pm3 + solution by adding HF solution, the precipitate has a pale pink color. The melting point of the anhydrous compound is 1338 ° C. When PmF3 · x H2O is heated, Promethium (III) oxyfluoride (PmOF) is formed, which is purple-pink in color.
Promethium (III) chloride (PmCl3) is purple and has a melting point of 655 ° C. When PmCl3 is heated in the presence of H2O, the pale pink Promethium (III) oxychloride (PmOCl) is obtained.
Promethium (III) bromide (PmBr3) is formed from Pm2O3 by heating in the dry HBr stream. It is red and has a melting point of 660 ° C.
Promethium (III) iodide (PmI3) can not be prepared from Pm2O3 by reaction with HI-H2 mixtures, but promethium (III) oxyiodide (PmOI) is formed instead. Reaction of Pm2O3 with molten AlI3 at 500 ° C produces the desired product. It is red and has a melting point of 695 ° C.
Promethium (III) hydroxide (Pm (OH) 3) is obtained from a hydrochloric acid Pm3 + solution by introducing NH3. Its color is violet pink.
Classifications according to the Ordinance on Hazardous Substances are not available, because they only include the chemical hazard and play a completely subordinate role against the radioactivity-based hazards. The latter also applies only if it is a relevant quantity of substance.

Usage

Due to the short-lived isotopes and the very low availability of this element is only in the smallest amounts of technical use. The 146Pm and 147Pm nuclides are used as stimulating beta emitters in luminous numbers of clocks and in cold light sources of signal systems.
In addition, the beta radiation of promethium is used for radiometric thickness measurement and level measurement.
Aerospace uses small radionuclide batteries with promethium.

Promethium price

Prices for promethium -> prices for rare earths