Untriseptium | |||||||||||||||||||||||||
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137Uts | |||||||||||||||||||||||||
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Appearance | |||||||||||||||||||||||||
unknown | |||||||||||||||||||||||||
General properties | |||||||||||||||||||||||||
Name, symbol, number | untriseptium, Uts, 137 | ||||||||||||||||||||||||
Pronunciation | /uːntraɪˈsɛptiəm/ | ||||||||||||||||||||||||
Element category | superactinides | ||||||||||||||||||||||||
Group, period, block | N/A, 8, g | ||||||||||||||||||||||||
Mass number | [396] (predicted) | ||||||||||||||||||||||||
Electron configuration | [Uuo] 5g116f37d18s28p2 (predicted)[1] 2, 8, 18, 32, 43, 21, 9, 4 (predicted)[1] | ||||||||||||||||||||||||
Physical properties | |||||||||||||||||||||||||
unknown | |||||||||||||||||||||||||
Atomic properties | |||||||||||||||||||||||||
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Most stable isotopes | |||||||||||||||||||||||||
Main article: Isotopes of untriseptium | |||||||||||||||||||||||||
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v • t • e • r |
Untriseptium (pron.: /uːntraɪˈsɛptiəm/), Uts, is the temporary name for element 137. Isotopes are predicted in the bands 450Uts to 393Uts, 372Uts to 363Uts, and 356Uts. There may be isotopes in the band from the neutron dripline to 451Uts, but it is not possible to predict which ones are possible. Reported half-lives are all less than 1 hr, and most are under 1 sec. Forty-one isotopes in the bands 450Uts to 433Uts and 423Uts to 401Uts are predicted to form. All Uts isotopes, predicted or guessed, will last less than 1000 sec after the event which led to their formation.
Nuclear properties[]
Information sources[]
While studies addressing specific issues have been carried out to very high N[2]. and to moderate Z[3], (Z,N) or (Z,A) maps predicting half-lives and decay modes are almost completely limited to the region below Z = 130 and N = 220. There appears to be only one such map which extends beyond that region and is accessible[4].
(Z,N) maps for half-life and decay mode in [4] extend as high as Z = 175 and N = 333. Half-lives are reported as bands3 orders of magnitude wide (0.001 - 1 sec, for example), and should be considered accurate only to within +/- orders of magnitude (presumably from band center. (A nuclide reported to be in the 0.001 - 1 sec band should be considered to have a possible half-life between 10-4.5 sec and 101.5 sec.) Decay modes are limited alpha emission, beta emission, proton emission, and fission; and to the principal one for each nuclide. There are areas where two modes (or more) may be important, meaning that small uncertainties is model parameters could have produced different results. It is also possible that cluster decay may become important above the neutron shell closures at N = 228 and 308.
[4] does have two significant weakness in the way data are presented. Nuclides which are beta-stable are identified by black squares, overwriting decay mode and half-life information. In addition, nuclides having half-lives less than 10-9 sec are not reported, which obscures the distinction between nuclides having half-lives in the 10-9 and 10-14 sec band and nuclear drops whose half-life is under 10-14 sec.
Above Z around 126, predictions in [4] may not reach the neutron dripline. This can be an important limitation because the only processes which can form nuclei at more than atoms / star quantity generate very neutron-rich nuclei. It is possible to to make a crude, but conservative (high N) guess for the dripline's location by averaging predicted values for even-N nuclei. See The Final Element.) It is also possible to guess at regions of the (Z,N) or (Z,A) plane in which a fission barrier high enough to permit nuclides exists by using a first-order, liquid drop model. (See Nuclear Guesswork.) Specific numbers are reported for these guesses, not with the expectation that they are accurate, but because they are consistent from element to element. They allow construction of a map which at least hints at where in the (Z,A) plane nuclides may be found.
Guessed properties[]
A simple liquid-drop picture indicates that 489Uts to 451Uts are unlikely to decay by neutron emission and are stable enough against fission to allow beta decay. Between 470Uts and 451Uts, [4] probably makes no predictions, but extrapolation from higher Z indicates that it would predict mainly short-lived, fission-decaying nuclides. Nuclear properties above 450Uts are highly uncertain, but it is possible that some relatively long-lived, beta-decaying isotopes of Uts are possible. It is possible to state that half-lives longer than 1 sec are implausible between the neutron dripline (nominally 489Uts) and 451Uts.
Predicted properties[]
Isotopes in the band 450Uts - 434Uts are predicted to decay by beta emission. Predicted half-lives are in the 0.001 - 1 sec range. Actual half-lives are probably a few milliseconds and increase with declining N as the number of decays required to reach beta stability falls[5].
Isotopes in the band 433Uts - 429Uts are predicted to decay by fission. It appears to be possible for structure to destabilize a nuclide[6], so the data reported appear to be realistic, Half-lives predicted are in the 0.001 - 1 sec range throughout the band. Beta emission is probably an important secondary decay mode.
Isotopes in the band 428Uts - 402Uts are predicted to decay by beta emission. Half-lives are predicted to lie between 0.001 and 1 sec. A fission decay branch probably exists for lighter isotopes in this band.
Between 401Uts and 397Uts, fission becomes the dominant decay mode of even-N isotopes, whose half-lives decline rapidly to < 10-09 sec. Odd-N isotopes beta-decay with half-lives in the 0.001-1 sec range.
Between 396Uts and 393Uts, predicted nuclear properties become difficult to understand. Half-lives and modes become somewhat random. Decay modes are predicted to be either beta emission or fission, with one exception. 394Uts is predicted to decay by alpha emission. That makes it unique among Uts isotopes, but also hints that it's decay mode may be an artifact. The only isotopes with half-lives predicted to exceed 1 sec are 394Uts and 396Uts (which is predicted to fission). Both are odd-odd nuclides, so can be expected to resist fission, but the abundance of short-lived odd-odd nuclides in their vicinity indicates that their half-lives do not greatly exceed 1 sec. Allowing 101.5 sec maximum half-life for those isotopes seems adequate. The remaining two isotopes are short-lived. 395Uts is predicted to decay by beta emission with a half-life in the 0.001 - 1 sec range and 393Uts is predicted to fission with a half-life in the 10-6 - 0.001 sec range.
There is a gap from 392Uts to 373Uts in which properties are not reported. These may be short lived nuclides or nuclear drops whose half-life is less than 10-14 sec. It appears to be the expected destabilized region above N = 228.
Nuclides are predicted at 372Uts and from 370Uts to 363Uts. All are predicted to decay by fission. Half-lives increase as A declines, reaching the 0.001 - 1 sec range by 365Uts (for which N = 228), then falling abruptly.
356Uts is reported to decay by alpha emission with a 10-6 - 0.001 sec half-life. It is not clear whether this is an artifact.
N = 258 CLOSURE
The model used to predict decay properties of Uts isotopes has a relatively weak neutron shell closure at N = 258. Some neutron-dripline studies have indicated a strong closure at N = 258. If that closure is strong, one or more isotopes in the band 396Uts to 386Uts may even have half-lives exceeding 1000 sec. Interpolating between 472Uhq and 293Cn gives a reasonable value for maximum half-life of any nuclides stabilized by a strong N = 258 closure of 0.5 yr. Either alpha decay or beta decay may occur in this band, but fission can be expected to be suppressed.
These are not predictions of decay properties for nuclides in the vicinity of N = 258. This entire exercise is qualitative guesswork. No numbers, but a tantalizing hint of what might be.
Occurence[]
Formation[]
Where nuclear drops between the neutron dripline (nominally 489Uts) and 451Uts can be nuclides, they may form. Heavier isotopes may form directly from disintegrating neutron star material, and the remainder may form via beta decay chains from lower-Z nuclides. Since some of these chains may be terminated at Z < 137 in short-lived, fission-decaying nuclides, it is not possible to say which isotopes of Uts in this range can form.
Nearly all nuclear drops in the bands 450Uts to 393Uts, 372Uts to 363Uts, and 356Uts are predicted to be nuclides. All are too far from the neutron dripline to form directly. It is possible to simulate the formation of nuclides via decay chains using data from [4] and assuming an initial distribution close to the neutron dripline. Details of the model are provided in "Nuclear Decay Chains at High A" in this wiki. Per that model, 41 predicted isotopes; 450Uts to 433Uts and 423Uts to 401Uts; can form.
Neutron capture may be able to produce nuclides up to A around 360 before fission attrition stops further growth. It is implausible that neutron capture can form any Uts isotope. A small amount of fission infall may contribute to nuclides up to A = 406 (nominal).
Persistence[]
433Uts and heavier isotopes will vanish within 1000 sec after a neutron star merger which led to their formation. 433Uts itself ends a beta-decay chain, but fissions with a half-life under 1 sec.
432Uts to 418Uts lie at higher Z than beta-decay chains which end in nuclides which decay by fission and have half-lives under 1 sec.
417Uts through 401Uts are predicted to be short-lived, beta-decaying species or to be unable to form because they lie at higher Z than beta-decay chains which end in nuclides which decay by fission with a half-life not much greater than 1 sec,
At 400Uts and below, all beta-decay chains end in short-lived, fissioning nuclides. No other isotopes of Uts persist for a significant time.
Calculations done under maximum half-life assumptions and with all nuclides initially populated still point to all isotopes of Uts vanishing within 105.5 (3.16E05) sec.
N = 258 SHELL CLOSURE
Some studies of the neutron dripline indicate a strong shell closure at N = 258, instead of the relatively weak one occurring in the predictive models, If so, and if peak half-lives in the region do approach 0.5 yr, it is possible that one or more isotopes in the band 396Uto to 386Uto may persist for up to 60 yrs. In addition, lighter isotopes in the band 385Uts to 376Uts may persist an equal lenght of time because they are daughers of long-lived precursors. Small quantities of several isotopes may be injected into a stellar system other than the one in which neutron star merger occurred.
Atomic properties[]
Electron structure of Uts has been predicted by several sources (see "Extended Periodic Table" in Wikipedia). Up to Z = 137, an atom's nucleus may be regarded as pointlike for the purpose of calculating electron configurations, which means predicted electron structure and behavior can be read more confidently. Its consensus electron configuration has been predicted[7] to be [Og] 5g11 6f4 8s2 8p21/2. (Note the 6f-7d change.)
Significance[]
Some (very few) call it "Feynmanium" because Feynman (supposedly) said it woud be the last possble element.
References[]
- ↑ 1.0 1.1 Electron configurations of the elements (data page) - Wikipedia
- ↑ for example, "Nuclear Energy Density Functionals: What Do We Really Know?"; Aurel Bulgac, Michael McNeil Forbes, and Shi Jin; Researchgate publication 279633220 or arXiv: 1506.09195v1 [nucl-th] 30 Jun 2015.
- ↑ for example "Fission Mechanism of Exotic Nuclei"; Research Group for Heavy Element Nuclear Science; http://asrc.jaea.go.jp/soshiki/gr/HENS-gr/np/research/pageFission_e.html.; 17 Sept 17.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 "Decay Modes and a Limit of Existence of Nuclei"; H. Koura; 4th Int. Conf. on the Chemistry and Physics of Transactinide Elements; Sept. 2011.
- ↑ "Nuclear Properties for Astrophysical Applications"; P. Moller & J. R. Nix; Los Alamos National Laboratory website; search by "LANL, T2", then "Nuclear Properties for Astrophysical Applications".
- ↑ "Magic Numbers of Ultraheavy Nuclei"; Vitali Denisov; Physics of Atomic Nuclei; researchgate.net/publications/225734594; July 2005.
- ↑ "Extended Periodic Table", Wikipedia.
Other references are found in the wiki articles cited.
(07-02-20)
9-Period Periodic Table of Elements | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 | 1 H |
2 He | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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2 | 3 Li |
4 Be |
5 B |
6 C |
7 N |
8 O |
9 F |
10 Ne | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
3 | 11 Na |
12 Mg |
13 Al |
14 Si |
15 P |
16 S |
17 Cl |
18 Ar | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
4 | 19 K |
20 Ca |
21 Sc |
22 Ti |
23 V |
24 Cr |
25 Mn |
26 Fe |
27 Co |
28 Ni |
29 Cu |
30 Zn |
31 Ga |
32 Ge |
33 As |
34 Se |
35 Br |
36 Kr | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
5 | 37 Rb |
38 Sr |
39 Y |
40 Zr |
41 Nb |
42 Mo |
43 Tc |
44 Ru |
45 Rh |
46 Pd |
47 Ag |
48 Cd |
49 In |
50 Sn |
51 Sb |
52 Te |
53 I |
54 Xe | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
6 | 55 Cs |
56 Ba |
57 La |
58 Ce |
59 Pr |
60 Nd |
61 Pm |
62 Sm |
63 Eu |
64 Gd |
65 Tb |
66 Dy |
67 Ho |
68 Er |
69 Tm |
70 Yb |
71 Lu |
72 Hf |
73 Ta |
74 W |
75 Re |
76 Os |
77 Ir |
78 Pt |
79 Au |
80 Hg |
81 Tl |
82 Pb |
83 Bi |
84 Po |
85 At |
86 Rn | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
7 | 87 Fr |
88 Ra |
89 Ac |
90 Th |
91 Pa |
92 U |
93 Np |
94 Pu |
95 Am |
96 Cm |
97 Bk |
98 Cf |
99 Es |
100 Fm |
101 Md |
102 No |
103 Lr |
104 Rf |
105 Db |
106 Sg |
107 Bh |
108 Hs |
109 Mt |
110 Ds |
111 Rg |
112 Cn |
113 Nh |
114 Fl |
115 Mc |
116 Lv |
117 Ts |
118 Og | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
8 | 119 Uue |
120 Ubn |
121 Ubu |
122 Ubb |
123 Ubt |
124 Ubq |
125 Ubp |
126 Ubh |
127 Ubs |
128 Ubo |
129 Ube |
130 Utn |
131 Utu |
132 Utb |
133 Utt |
134 Utq |
135 Utp |
136 Uth |
137 Uts |
138 Uto |
139 Ute |
140 Uqn |
141 Uqu |
142 Uqb |
143 Uqt |
144 Uqq |
145 Uqp |
146 Uqh |
147 Uqs |
148 Uqo |
149 Uqe |
150 Upn |
151 Upu |
152 Upb |
153 Upt |
154 Upq |
155 Upp |
156 Uph |
157 Ups |
158 Upo |
159 Upe |
160 Uhn |
161 Uhu |
162 Uhb |
163 Uht |
164 Uhq |
165 Uhp |
166 Uhh |
167 Uhs |
168 Uho |
169 Uhe |
170 Usn |
171 Usu |
172 Usb | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
9 | 173 Ust |
174 Usq | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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