On April 24, 2008, a group led by Marinov at Hebrew University of Jerusalem claimed to have found single atoms of unbibium-292 in natural thorium deposits at an abundance of 10−11 to 10−12 relative to thorium.[1] This was the first time in sixty-nine years that a new element had been claimed to be discovered in nature, after Marguerite Perey's 1939 discovery of francium.[a] The claim of Marinov et al. was criticized by a part of the scientific community, and Marinov said he submitted the article to the journals Nature and Nature Physics but both turned it down without sending it for peer review.[2] The unbibium-292 atoms were claimed to be superdeformed or hyperdeformednuclear isomers, with a half-life of at least 108 years.[3]
A criticism of the technique, previously used in purportedly identifying lighter thorium isotopes by mass spectrometry,[4] was published in Physical Review C in 2008.[5] A rebuttal by the Marinov group was published in Physical Review C after the published comment.[6]
A repeat of the thorium experiment using the superior method of accelerator mass spectrometry (AMS) failed to confirm the results, despite a 100-fold better sensitivity.[7] This result throws considerable doubt on the results of the Marinov collaboration with regards to their claims of long-lived isotopes of thorium,[4]roentgenium[8] and unbibium.[1] It is still possible that traces of unbibium might exist in some thorium samples, though given current understanding of superheavy elements, this is very unlikely.[3]
Amnon Marinov lived in Jerusalem, Israel with his wife Rachel; they have four children and six grandchildren. His father, Haim Marinov (1904–2001), was the deputy mayor of Jerusalem from 1964 until 1973. His father-in-law, Ya'akov Maimon (1902–1977), was the inventor of Hebrew stenography and received the Israel Prize in 1976 for his lifelong voluntary work teaching Hebrew to new immigrants all over the country.[9] Amnon Marinov died on December 7, 2011.
Notes
^Four more elements were discovered after 1939 through synthesis, but were later found to also occur naturally: these were promethium, astatine, neptunium, and plutonium, all of which had been found by 1945.
References
^ abMarinov, A.; Rodushkin, I.; Kolb, D.; Pape, A.; Kashiv, Y.; Brandt, R.; Gentry, R. V.; Miller, H. W. (2010). "Evidence for a long-lived superheavy nucleus with atomic mass number A=292 and atomic number Z=~122 in natural Th". International Journal of Modern Physics E. 19 (1): 131–140. arXiv:0804.3869. Bibcode:2010IJMPE..19..131M. doi:10.1142/S0218301310014662. S2CID117956340.
^ abEmsley, John (2011). Nature's Building Blocks: An A-Z Guide to the Elements (New ed.). New York, NY: Oxford University Press. p. 588. ISBN978-0-19-960563-7.
^ abMarinov, A.; Rodushkin, I.; Kashiv, Y.; Halicz, L.; Segal, I.; Pape, A.; Gentry, R. V.; Miller, H. W.; Kolb, D.; Brandt, R. (2007). "Existence of long-lived isomeric states in naturally-occurring neutron-deficient Th isotopes". Phys. Rev. C. 76 (2): 021303(R). arXiv:nucl-ex/0605008. Bibcode:2007PhRvC..76b1303M. doi:10.1103/PhysRevC.76.021303. S2CID119443571.
^R. C. Barber; J. R. De Laeter (2009). "Comment on "Existence of long-lived isomeric states in naturally-occurring neutron-deficient Th isotopes"". Phys. Rev. C. 79 (4): 049801. Bibcode:2009PhRvC..79d9801B. doi:10.1103/PhysRevC.79.049801.
^A. Marinov; I. Rodushkin; Y. Kashiv; L. Halicz; I. Segal; A. Pape; R. V. Gentry; H. W. Miller; D. Kolb; R. Brandt (2009). "Reply to "Comment on 'Existence of long-lived isomeric states in naturally-occurring neutron-deficient Th isotopes'"". Phys. Rev. C. 79 (4): 049802. Bibcode:2009PhRvC..79d9802M. doi:10.1103/PhysRevC.79.049802.