Promethium shows only one stable oxidation state of +3. In 1902 Bohuslav Brauner suggested that there was a then-unknown element with properties intermediate between those of the known elements neodymium (60) and samarium (62); this was confirmed in 1914 by Henry Moseley, who, having measured the atomic numbers of all the elements then known, found that atomic number 61 was missing.
Because of the short half-life of promethium isotopes, they should be formed near the surface of those stars. ==History== ===Searches for element 61=== In 1902, Czech chemist Bohuslav Brauner found out that the differences in properties between neodymium and samarium were the largest between any two consecutive lanthanides in the sequence then known; as a conclusion, he suggested there was an element with intermediate properties between them.
Promethium shows only one stable oxidation state of +3. In 1902 Bohuslav Brauner suggested that there was a then-unknown element with properties intermediate between those of the known elements neodymium (60) and samarium (62); this was confirmed in 1914 by Henry Moseley, who, having measured the atomic numbers of all the elements then known, found that atomic number 61 was missing.
This prediction was supported in 1914 by Henry Moseley who, having discovered that atomic number was an experimentally measurable property of elements, found that a few atomic numbers had no known corresponding elements: the gaps were 43, 61, 72, 75, 85, and 87.
The results were published in 1926, but the scientists claimed that the experiments were done in 1924.
In 1926, two groups (one Italian and one American) claimed to have isolated a sample of element 61; both "discoveries" were soon proven to be false.
The results were published in 1926, but the scientists claimed that the experiments were done in 1924.
Also in 1926, a group of scientists from the University of Illinois at Urbana–Champaign, Smith Hopkins and Len Yntema published the discovery of element 61.
In fact, promethium-148m has a longer half-life than its ground state, promethium-148. ==Occurrence== In 1934, Willard Libby reported that he had found weak beta activity in pure neodymium, which was attributed to a half-life over 1012 years.
Both of these reported discoveries were shown to be erroneous because the spectrum line that "corresponded" to element 61 was identical to that of didymium; the lines thought to belong to element 61 turned out to belong to a few impurities (barium, chromium, and platinum). In 1934, Josef Mattauch finally formulated the isobar rule.
In 1938, during a nuclear experiment conducted at The Ohio State University, a few radioactive nuclides were produced that certainly were not radioisotopes of neodymium or samarium, but there was a lack of chemical proof that element 61 was produced, and the discovery was not generally recognized.
From 1938, a nuclear experiment was conducted by H.
Nuclides were produced in 1941 which were not radioisotopes of neodymium or samarium, and the name "cyclonium" was proposed, but there was a lack of chemical proof that element 61 was produced and the discovery not largely recognized. ===Discovery and synthesis of promethium metal=== Promethium was first produced and characterized at Oak Ridge National Laboratory (Clinton Laboratories at that time) in 1945 by Jacob A.
Promethium was first produced and characterized at Oak Ridge National Laboratory in 1945 by the separation and analysis of the fission products of uranium fuel irradiated in a graphite reactor.
Nuclides were produced in 1941 which were not radioisotopes of neodymium or samarium, and the name "cyclonium" was proposed, but there was a lack of chemical proof that element 61 was produced and the discovery not largely recognized. ===Discovery and synthesis of promethium metal=== Promethium was first produced and characterized at Oak Ridge National Laboratory (Clinton Laboratories at that time) in 1945 by Jacob A.
Coryell by separation and analysis of the fission products of uranium fuel irradiated in the graphite reactor; however, being too busy with military-related research during World War II, they did not announce their discovery until 1947.
Another method is to bombard uranium-238 with fast neutrons to cause fast fission, which, among multiple reaction products, creates promethium-147. As early as the 1960s, Oak Ridge National Laboratory could produce 650 grams of promethium per year and was the world's only large-volume synthesis facility.
However, a sample of the metal was made only in 1963. There are two possible sources for natural promethium: rare decays of natural europium-151 (producing promethium-147) and uranium (various isotopes).
The spelling was then changed to "promethium," as this was in accordance with most other metals. In 1963, promethium(III) fluoride was used to make promethium metal.
The first promethium-based battery was assembled in 1964 and generated "a few milliwatts of power from a volume of about 2 cubic inches, including shielding". Promethium is also used to measure the thickness of materials by evaluating the amount of radiation from a promethium source that passes through the sample.
in the early 1980s, but will possibly be resumed after 2010 at the High Flux Isotope Reactor.
in the early 1980s, but will possibly be resumed after 2010 at the High Flux Isotope Reactor.
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