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The names for the chemical elements 104 to 106 were the subject of a major controversy starting in the 1960s, described by some nuclear chemists as the Transfermium Wars [1] [2] because it concerned the elements following fermium (element 100) on the periodic table.
This controversy arose from disputes between American scientists and Soviet scientists as to which had first isolated these elements. The final resolution of this controversy in 1997 also decided the names of elements 107 to 109.
By convention, naming rights for newly discovered chemical elements go to their discoverers. For elements 104, 105, and 106, there was a controversy between Soviet researchers at the Joint Institute for Nuclear Research and American researchers at Lawrence Berkeley National Laboratory regarding which group had discovered them first. Both parties suggested their own names for elements 104 and 105, not recognizing the other's name.
The American name of seaborgium for element 106 was also objectionable to some, because it referred to American chemist Glenn T. Seaborg who was still alive at the time this name was proposed. [3] (Einsteinium and fermium had also been proposed as names of new elements while Albert Einstein and Enrico Fermi were still living, but only made public after their deaths, due to Cold War secrecy.)
The two principal groups which were involved in the conflict over element naming were:
and, as a kind of arbiter,
The German group at the Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, who had (undisputedly) discovered elements 107 to 109, were dragged into the controversy when the Commission suggested that the name "hahnium", proposed for element 105 by the Americans, be used for GSI's element 108 instead.
Group | Atomic number | Name | Eponym |
---|---|---|---|
American | 104 | Rutherfordium | Ernest Rutherford |
105 | Hahnium | Otto Hahn | |
106 | Seaborgium | Glenn T. Seaborg | |
Russian | 104 | Kurchatovium | Igor Kurchatov |
105 | Nielsbohrium | Niels Bohr |
The names suggested for the elements 107 to 109 by the German group were: [4]
Atomic number | Name | Eponym |
---|---|---|
107 | Nielsbohrium | Niels Bohr |
108 | Hassium | Hesse, Germany |
109 | Meitnerium | Lise Meitner |
In 1994, the IUPAC Commission on Nomenclature of Inorganic Chemistry proposed the following names:
Atomic number | Name | Eponym |
---|---|---|
104 | Dubnium | Dubna, Russia |
105 | Joliotium | Frédéric Joliot-Curie |
106 | Rutherfordium | Ernest Rutherford |
107 | Bohrium | Niels Bohr |
108 | Hahnium | Otto Hahn |
109 | Meitnerium | Lise Meitner |
This attempted to resolve the dispute by sharing the namings of the disputed elements between Russians and Americans, replacing the name for 104 with one honoring the Dubna research center, and not naming 106 after Seaborg.
This solution drew objections from the American Chemical Society (ACS) on the grounds that the right of the American group to propose the name for element 106 was not in question, and that group should have the right to name the element. Indeed, IUPAC decided that the credit for the discovery of element 106 should be awarded to Berkeley.
Along the same lines, the German group protested against naming element 108 by the American suggestion "hahnium", mentioning the long-standing convention that an element is named by its discoverers. [5]
In addition, given that many American books had already used rutherfordium and hahnium for 104 and 105, the ACS objected to those names being used for other elements.
In 1995, IUPAC abandoned the controversial rule and established a committee of national representatives aimed at finding a compromise. They suggested seaborgium for element 106 in exchange for the removal of all the other American proposals, except for the established name lawrencium for element 103. The equally entrenched name nobelium for element 102 was replaced by flerovium after Georgy Flyorov, following the recognition by the 1993 report that that element had been first synthesized in Dubna. This was rejected by American scientists and the decision was retracted. [6] The name flerovium was later used for element 114. [7]
In 1996, IUPAC held another meeting, reconsidered all names in hand, and accepted another set of recommendations; finally, it was approved and published in 1997 on the 39th IUPAC General Assembly in Geneva, Switzerland. [8] Element 105 was named dubnium (Db), after Dubna in Russia, the location of the JINR; the American suggestions were used for elements 102, 103, 104, and 106. The name dubnium had been used for element 104 in the previous IUPAC recommendation. The American scientists "reluctantly" approved this decision. [9] IUPAC pointed out that the Berkeley laboratory had already been recognized several times, in the naming of berkelium, californium, and americium, and that the acceptance of the names rutherfordium and seaborgium for elements 104 and 106 should be offset by recognizing JINR's contributions to the discovery of elements 104, 105, and 106. [10]
The following names were agreed in 1997 on the 39th IUPAC General Assembly in Geneva, Switzerland:
Atomic number | Name | Eponym |
---|---|---|
104 | Rutherfordium | Ernest Rutherford |
105 | Dubnium | Dubna, Russia |
106 | Seaborgium | Glenn Theodore Seaborg |
107 | Bohrium | Niels Bohr |
108 | Hassium | Hesse, Germany |
109 | Meitnerium | Lise Meitner |
Thus, the convention of the discoverer's right to name their elements was respected for elements 106 to 109, [11] and the two disputed claims were "shared" between the two opponents.
Z | Mendeleev | Systematic | American | Russian | German | Compromise 92 | IUPAC 94 | ACS 94 | IUPAC 95 | IUPAC 97 | Present |
---|---|---|---|---|---|---|---|---|---|---|---|
101 | eka-thulium | (unnilunium) | mendelevium | — | — | mendelevium | mendelevium | mendelevium | mendelevium | mendelevium | mendelevium |
102 | eka-ytterbium | (unnilbium) | nobelium | joliotium | — | joliotium | nobelium | nobelium | flerovium | nobelium | nobelium |
103 | eka-lutetium | (unniltrium) | lawrencium | rutherfordium | — | lawrencium | lawrencium | lawrencium | lawrencium | lawrencium | lawrencium |
104 | eka-hafnium | unnilquadium | rutherfordium | kurchatovium | — | meitnerium | dubnium | rutherfordium | dubnium | rutherfordium | rutherfordium |
105 | eka-tantalum | unnilpentium | hahnium | nielsbohrium | — | kurchatovium | joliotium | hahnium | joliotium | dubnium | dubnium |
106 | eka-tungsten | unnilhexium | seaborgium | — | — | rutherfordium | rutherfordium | seaborgium | seaborgium | seaborgium | seaborgium |
107 | eka-rhenium | unnilseptium | — | — | nielsbohrium | nielsbohrium | bohrium | nielsbohrium | nielsbohrium | bohrium | bohrium |
108 | eka-osmium | unniloctium | — | — | hassium | hassium | hahnium | hassium | hahnium | hassium | hassium |
109 | eka-iridium | unnilennium | — | — | meitnerium | hahnium | meitnerium | meitnerium | meitnerium | meitnerium | meitnerium |
110 | eka-platinum | ununnilium | hahnium | becquerelium | darmstadtium | — | — | — | — | — | darmstadtium |
111 | eka-gold | unununium | — | — | roentgenium | — | — | — | — | — | roentgenium |
112 | eka-mercury | ununbium | — | — | copernicium | — | — | — | — | — | copernicium |
proposal eventually accepted. name eventually used for a different element. Flerovium, IUPAC 1995 proposal for element 102, was adopted uncontroversially for element 114 (eka-lead). |
In some countries, as Poland, Denmark, [12] India, [13] Indonesia [14] prior to 1997 element 104 had a Soviet proposal kurchatovium and element 105 had an American proposal hahnium.
Bohrium is a synthetic chemical element; it has symbol Bh and atomic number 107. It is named after Danish physicist Niels Bohr. As a synthetic element, it can be created in particle accelerators but is not found in nature. All known isotopes of bohrium are highly radioactive; the most stable known isotope is 270Bh with a half-life of approximately 2.4 minutes, though the unconfirmed 278Bh may have a longer half-life of about 11.5 minutes.
Dubnium is a synthetic chemical element; it has symbol Db and atomic number 105. It is highly radioactive: the most stable known isotope, dubnium-268, has a half-life of about 16 hours. This greatly limits extended research on the element.
Hassium is a synthetic chemical element; it has symbol Hs and atomic number 108. Hassium is highly radioactive: its most stable known isotopes have half-lives of approximately ten seconds. One of its isotopes, 270Hs, has magic numbers of both protons and neutrons for deformed nuclei, which gives it greater stability against spontaneous fission. Hassium is a superheavy element; it has been produced in a laboratory only in very small quantities by fusing heavy nuclei with lighter ones. Natural occurrences of the element have been hypothesised but never found.
Lawrencium is a synthetic chemical element; it has symbol Lr and atomic number 103. It is named in honor of Ernest Lawrence, inventor of the cyclotron, a device that was used to discover many artificial radioactive elements. A radioactive metal, lawrencium is the eleventh transuranic element and the last member of the actinide series. Like all elements with atomic number over 100, lawrencium can only be produced in particle accelerators by bombarding lighter elements with charged particles. Fourteen isotopes of lawrencium are currently known; the most stable is 266Lr with half-life 11 hours, but the shorter-lived 260Lr is most commonly used in chemistry because it can be produced on a larger scale.
Meitnerium is a synthetic chemical element; it has symbol Mt and atomic number 109. It is an extremely radioactive synthetic element. The most stable known isotope, meitnerium-278, has a half-life of 4.5 seconds, although the unconfirmed meitnerium-282 may have a longer half-life of 67 seconds. The GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany, first created this element in 1982. It is named after Lise Meitner.
Nobelium is a synthetic chemical element; it has symbol No and atomic number 102. It is named in honor of Alfred Nobel, the inventor of dynamite and benefactor of science. A radioactive metal, it is the tenth transuranic element and is the penultimate member of the actinide series. Like all elements with atomic number over 100, nobelium can only be produced in particle accelerators by bombarding lighter elements with charged particles. A total of twelve nobelium isotopes are known to exist; the most stable is 259No with a half-life of 58 minutes, but the shorter-lived 255No is most commonly used in chemistry because it can be produced on a larger scale.
Rutherfordium is a synthetic chemical element; it has symbol Rf and atomic number 104. It is named after physicist Ernest Rutherford. As a synthetic element, it is not found in nature and can only be made in a particle accelerator. It is radioactive; the most stable known isotope, 267Rf, has a half-life of about 48 minutes.
Seaborgium is a synthetic chemical element; it has symbol Sg and atomic number 106. It is named after the American nuclear chemist Glenn T. Seaborg. As a synthetic element, it can be created in a laboratory but is not found in nature. It is also radioactive; the most stable known isotope, 269Sg, has a half-life of approximately 14 minutes.
A synthetic element is one of 24 known chemical elements that do not occur naturally on Earth: they have been created by human manipulation of fundamental particles in a nuclear reactor, a particle accelerator, or the explosion of an atomic bomb; thus, they are called "synthetic", "artificial", or "man-made". The synthetic elements are those with atomic numbers 95–118, as shown in purple on the accompanying periodic table: these 24 elements were first created between 1944 and 2010. The mechanism for the creation of a synthetic element is to force additional protons into the nucleus of an element with an atomic number lower than 95. All known synthetic elements are unstable, but they decay at widely varying rates: the half-lives of their longest-lived isotopes range from microseconds to millions of years.
The transuranium elements are the chemical elements with atomic numbers greater than 92, which is the atomic number of uranium. All of them are radioactively unstable and decay into other elements. With the exception of neptunium and plutonium which have been found in trace amounts in nature, none occur naturally on Earth and they are synthetic.
Darmstadtium is a synthetic chemical element; it has symbol Ds and atomic number 110. It is extremely radioactive: the most stable known isotope, darmstadtium-281, has a half-life of approximately 14 seconds. Darmstadtium was first created in 1994 by the GSI Helmholtz Centre for Heavy Ion Research in the city of Darmstadt, Germany, after which it was named.
Livermorium is a synthetic chemical element; it has symbol Lv and atomic number 116. It is an extremely radioactive element that has only been created in a laboratory setting and has not been observed in nature. The element is named after the Lawrence Livermore National Laboratory in the United States, which collaborated with the Joint Institute for Nuclear Research (JINR) in Dubna, Russia, to discover livermorium during experiments conducted between 2000 and 2006. The name of the laboratory refers to the city of Livermore, California, where it is located, which in turn was named after the rancher and landowner Robert Livermore. The name was adopted by IUPAC on May 30, 2012. Five isotopes of livermorium are known, with mass numbers of 288 and 290–293 inclusive; the longest-lived among them is livermorium-293 with a half-life of about 60 milliseconds. A sixth possible isotope with mass number 294 has been reported but not yet confirmed.
Moscovium is a synthetic chemical element; it has symbol Mc and atomic number 115. It was first synthesized in 2003 by a joint team of Russian and American scientists at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. In December 2015, it was recognized as one of four new elements by the Joint Working Party of international scientific bodies IUPAC and IUPAP. On 28 November 2016, it was officially named after the Moscow Oblast, in which the JINR is situated.
Copernicium is a synthetic chemical element; it has symbol Cn and atomic number 112. Its known isotopes are extremely radioactive, and have only been created in a laboratory. The most stable known isotope, copernicium-285, has a half-life of approximately 30 seconds. Copernicium was first created in 1996 by the GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany. It was named after the astronomer Nicolaus Copernicus on his 537th birthday.
Flerovium is a superheavy synthetic chemical element; it has symbol Fl and atomic number 114. It is an extremely radioactive element, named after the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research in Dubna, Russia, where the element was discovered in 1999. The lab's name, in turn, honours Russian physicist Georgy Flyorov. IUPAC adopted the name on 30 May 2012. The name and symbol had previously been proposed for element 102 (nobelium), but was not accepted by IUPAC at that time.
Albert Ghiorso was an American nuclear scientist and co-discoverer of a record 12 chemical elements on the periodic table. His research career spanned six decades, from the early 1940s to the late 1990s.
A period 7 element is one of the chemical elements in the seventh row of the periodic table of the chemical elements. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behavior of the elements as their atomic number increases: a new row is begun when chemical behavior begins to repeat, meaning that elements with similar behavior fall into the same vertical columns. The seventh period contains 32 elements, tied for the most with period 6, beginning with francium and ending with oganesson, the heaviest element currently discovered. As a rule, period 7 elements fill their 7s shells first, then their 5f, 6d, and 7p shells in that order, but there are exceptions, such as uranium.
Superheavy elements, also known as transactinide elements, transactinides, or super-heavy elements, or superheavies for short, are the chemical elements with atomic number greater than 103. The superheavy elements are those beyond the actinides in the periodic table; the last actinide is lawrencium. By definition, superheavy elements are also transuranium elements, i.e., having atomic numbers greater than that of uranium (92). Depending on the definition of group 3 adopted by authors, lawrencium may also be included to complete the 6d series.
Chemical elements may be named from various sources: sometimes based on the person who discovered it, or the place it was discovered. Some have Latin or Greek roots deriving from something related to the element, for example some use to which it may have been put.