Global InformationUnbihexium information
| Theoretical element | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Unbihexium | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Pronunciation | /ˌuːnbaɪˈhɛksiəm/ | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Alternative names | element 126, eka-plutonium | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Unbihexium in the periodic table | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Atomic number (Z) | 126 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Group | g-block groups (no number) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Period | period 8 (theoretical, extended table) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Block | g-block | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Electron configuration | predictions vary, see text | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Physical properties | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Phase at STP | unknown | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Atomic properties | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Oxidation states | (+1), (+2), (+4), (+6), (+8) (predicted)[1] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Other properties | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| CAS Number | 54500-77-5 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| History | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Naming | IUPAC systematic element name | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Unbihexium, also known as element 126 or eka-plutonium, is a hypothetical chemical element; it has atomic number 126 and placeholder symbol Ubh. Unbihexium and Ubh are the temporary IUPAC name and symbol, respectively, until the element is discovered, confirmed, and a permanent name is decided upon. In the periodic table, unbihexium is expected to be a g-block superactinide and the eighth element in the 8th period. Unbihexium has attracted attention among nuclear physicists, especially in early predictions targeting properties of superheavy elements, for 126 may be a magic number of protons near the center of an island of stability, leading to longer half-lives, especially for 310Ubh or 354Ubh which may also have magic numbers of neutrons.[2]
Early interest in possible increased stability led to the first attempted synthesis of unbihexium in 1971 and searches for it in nature in subsequent years. Despite several reported observations, more recent studies suggest that these experiments were insufficiently sensitive; hence, no unbihexium has been found naturally or artificially. Predictions of the stability of unbihexium vary greatly among different models; some suggest the island of stability may instead lie at a lower atomic number, closer to copernicium and flerovium.
Unbihexium is predicted to be a chemically active superactinide, exhibiting a variety of oxidation states from +1 to +8, and possibly being a heavier congener of plutonium. An overlap in energy levels of the 5g, 6f, 7d, and 8p orbitals is also expected, which complicates predictions of chemical properties for this element.
- ^ Pyykkö, Pekka (2011). "A suggested periodic table up to Z ≤ 172, based on Dirac–Fock calculations on atoms and ions". Physical Chemistry Chemical Physics. 13 (1): 161–8. Bibcode:2011PCCP...13..161P. doi:10.1039/c0cp01575j. PMID 20967377.
- ^ Cite error: The named reference
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