Search for Superheavy Elements in Monazite Ore from Madagascar

Stéphan, C.; Epherre, M.; Cieślak, E.; Sowiński, M.; Tys, J.

doi:10.1103/physrevlett.37.1534

Cited by 20 publications

(6 citation statements)

References 10 publications

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“…These compounds are described by two parameters r average = (1 − 2x) [9] r M 3+ + x [9] r M 2+ + x [9] r M 4+ and r ratio = [(1 − x) [9] r M 3+ + x [9] r M 2+ ]/[(1 − x) [9] r M 3+ + x [9] r M 4+ ] (where [9] r M is the ionic radius of the M element in the ninefold coordination 155 ). The upper and lower values of these parameters are 1.216Å ≥ r average ≥ 1.107Å and 1.238 ≥ r ratio ≥ 1.…”

Section: Criteria For the Stability Of The Monazite Structurementioning

confidence: 99%

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Crystal chemistry of the monazite structure

Clavier

Podor

Dacheux

2011

Journal of the European Ceramic Society

354

243

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Section: Criteria For the Stability Of The Monazite Structurementioning

confidence: 99%

“…7,8 However, no evidence for the existence of such elements was obtained. [9][10][11] Due to some interesting physical and chemical properties (high fusion temperature, optical emissivity, high resistance to aqueous and molten glass corrosion or to radiation damage, . .…”

Section: Introductionmentioning

confidence: 99%

Crystal chemistry of the monazite structure

Clavier

Podor

Dacheux

2011

Journal of the European Ceramic Society

354

243

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“…On the whole, based on experiments on SHE searches one can conclude that if these elements do exist, their concentration in the Earth's crust and meteorites is very low, not exceeding, on average, lo-'' g/g. This conclusion follows from experiments using neutron detectors (Flerov etal 1971b, 1974b, c, 1975b, Cheifetz et a1 1972, Stoughton et a1 1973, Masiov et a1 1974, Ketelle et a1 1976, Fireman et a1 1979, Halperin et a1 1981 and mass separators (Sowinski et a1 1971, Stephan et a1 1975, Epherre and Klapisch 1976, McMinn et a1 1976, in which, on the whole, several hundreds of samples of different composition and origin were investigated. The overwhelming majority of the samples were studied using neutron detectors.…”

Section: 43mentioning

confidence: 85%

Superheavy nuclei

1983

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The problem of the nuclear stability of superheavy chemical elements began to attract a great deal of attention soon after the methods of calculating their nuclear deformation energy had been developed and significant fission barriers had been predicted for superheavy nuclei having proton and neutron numbers close to the magic numbers 2 = 114 and N = 184.Experiments to produce superheavy nuclei in heavy-ion reactions have so far been unsuccessful. However, some data show that the possibilities of producing cold compound nuclei were not used in the 48Ca-induced reactions. Therefore the corresponding experiments should be repeated. It is not excluded that superheavy element (SHE) nuclei could be produced in deep inelastic transfer reactions involved in the system Cm + 2 3 8 ~.Consideration of the mechanisms of nucleosynthesis and halflife calculations show that there is a small probability for superheavy nuclei to exist in nature. In studies of the tracks of cosmic-ray nuclei in meteoritic olivines some long tracks, supposedly due to nuclei with 2 = 110, have been observed. Their flux is nearly 300 times smaller than those of the thorium-uranium group nuclei.Searches for superheavy elements in some primitive meteorites and hot brines have resulted in the detection of a spontaneously fissioning nuclide, possibly belonging to a new island of stability. The low concentration of this nuclide (about g/g (1 part in in the Allende meteorite) makes its identification difficult. Searches should be made for geological samples whose formation process might lead to a greater concentration of the hypothetical superheavy elements relative to the average concentration in the Earth's crust. 248

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“…Partial closure to this episode was achieved when extremely sensitive nuclear fission experiments designed to probe for superheavy nuclei also yielded negative results [174,175]. However, as recently as 2010 Gentry was involved in claims for discovery of the isotope 122292122 in naturally occurring thorium by inductively coupled plasma-sector field mass spectroscopy [176].…”

Section: Primordial Superheavy Elementsmentioning

confidence: 99%

Henry Moseley, X-ray spectroscopy and the periodic table

Egdell

Bruton

2020

Phil. Trans. R. Soc. A.

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Just over 100 years ago, Henry Moseley carried out a systematic series of experiments which showed that the frequencies of the X-rays emitted from an elemental target under bombardment by cathode rays were characteristic of that element and could be used to identify the charge on its atomic nucleus. This led to a reorganization of the periodic table, with chemical elements now arranged on the basis of atomic number Z rather than atomic weight A, as had been the case in previous tables, including those developed by Mendeleev. Moseley also showed that there were four ‘missing elements’ before gold. With further measurements up to uranium Z = 92, the Swedish physicist Manne Siegbahn identified two more missing elements. This paper provides an introduction to Moseley and his experiments and then traces attempts to ‘discover’ missing elements by X-ray spectroscopy. There were two successes with hafnium (Z = 72) and rhenium (Z = 75), but many blind alleys and episodes of self-deception when dealing with elements 43, 61, 85 and 87. These all turned out to be radioactive, with extremely small natural abundances: all required synthesis by a nuclear reaction, with radiological characterization in the first instance. Finally, the paper moves on to consider the role of X-ray spectroscopy in exploring the periodic table beyond uranium. Although the discovery of artificial radioactive elements with Z > 92 again depended on nucleosynthesis and radiological characterization, measurement of the frequencies or energies of characteristic X-rays remains the ultimate goal in proving the existence of an element. This article is part of the theme issue ‘Mendeleev and the periodic table’.

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Search for Superheavy Elements in Monazite Ore from Madagascar

Cited by 20 publications

References 10 publications

Crystal chemistry of the monazite structure

Crystal chemistry of the monazite structure

Superheavy nuclei

Henry Moseley, X-ray spectroscopy and the periodic table

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