Untrinilium

Untrinilium
130Utn
- ↑ Utn ↓ Uon Extended periodic table unbiennium ← untrinilium → untriunium
Appearance
unknown
General properties
Name, symbol, number	untrinilium, Utn, 130
Pronunciation	/uːntraɪˈnɪliəm/
Element category	superactinides
Group, period, block	N/A, 8, g
Mass number	not applicable
Electron configuration	[Uuo] 5g66f28s28p2 (predicted) 2, 8, 18, 32, 38, 20, 8, 4 (predicted)
Physical properties
unknown
Atomic properties
unknown
Most stable isotopes
Main article: Isotopes of untrinilium
iso NA half-life DM DE (MeV) DP 346Utn (predicted) syn
v • t • e • r

Untrinilium, Utn, is the temporary name for element 130. Isotopes are predicted within the bands ⁴³⁸Utn to ³⁷⁵Utn, ³⁶⁹Utn to ³⁵⁵Utn, and ³¹⁷Utn to ²⁹⁹Utn. There may be isotopes in the band from the neutron dripline to ⁴³⁹Utn, 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. Sixty one isotopes within the bands ⁴³⁸Utn to ⁴²³Utn (even-N only), ⁴²²Utn to ³⁷¹Utn, and ³⁶²Utn are predicted to form. All Utn 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⁽¹⁾. and to moderate Z⁽²⁾, (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⁽³⁾.

(Z,N) maps for half-life and decay mode in Ref. 3 extend as high as Z = 175 and N = 333. Half-lives are reported as bands 3 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 10^1.5 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.

Ref. 3 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^-09 sec are not reported, which obscures the distinction between nuclides having half-lives in the 10^-09 and 10^-14 sec band and nuclear drops whose half-life is under 10^-14 sec.

Above Z around 126, predictions in Ref. 3 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" (this wiki).} 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" (this wiki).} 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 even-N particles in the range ⁴⁶²Utn to ⁴³⁹Utn are unlikely to decay by neutron emission and are stable enough against fission to allow beta decay. Ref. 3 makes no predictions for this region, but extrapolation from higher Z indicates that it may predict some short-lived, fission-decaying nuclides. It does seem likely, though, that beta decay will be common for even-N nuclides in this range. Odd-N particles can be expected to be nuclear drops which decay by neutron emission too quickly to qualify as nuclides.

PREDICTED PROPERTIES

Even-N isotopes in the band ⁴³⁸Utn - ⁴³¹Utn are predicted to decay by beta emission. Since predicted half-lives are in the 10^-06 - 0.001 sec range and beta decay partial half-lives far from stability have a minimum near 0.001 sec⁽⁴⁾, that is about where half-lives should lie. Odd-N nuclear drops are predicted to decay by neutron emission before they have time to become nuclides.

Even-N isotopes in the band ⁴³⁰Utn - ⁴²³Utn are predicted to decay by a mixture of beta emission and fission, with fission dominant in most cases. It appears to be possible for structure to destabilize a nuclide⁽⁵⁾, so the data reported appear to be realistic, despite the high N/Z ratio. Half-lives are masked by other features of the map, but the properties of beta decay (see above) indicate that half-lives close to 0.001 sec are likely. Odd-N drops in this band decay by neutron emission.

Isotopes in the band ⁴²²Utn - ⁴²¹Utn are predicted to have a dominant fission decay branch. Predicted half-lives are in the 0.001 - 1 sec range, but will probably be near 0.001 sec. Neutron emission is a factor only above this band.

Isotopes in the band ⁴²⁰Utn - ³⁹⁹Utn are predicted to decay by beta emission,with half-lives predicted to lie between 0.001 and 1 sec.

Isotopes in the band ³⁹⁸Utn - ³⁸⁸Utn are predicted to decay with half-lives are predicted in the 0.001 - 1 sec range. Broadly, fission is the dominant decay mode in even-N isotopes (4 of 6) and beta emission is the dominant mode in odd-N isotopes (4 of 5). It is highly probable that both decay modes occur in all isotopes.

Between ³⁸⁷Utn and ³⁸¹Utn, odd-N isotopes are predicted to decay by fission and have half-lives in the 10^-09 - 10^-06 sec range. Even-N isotopes are predicted to decay by beta emission and have half-lives in the 0.001 - 1 sec range. This is the opposite of what would be expected. Also, ⁴⁸⁴Utn is predicted to have a half life < 10^-09 sec and presumably decay by fission. This band is confusing, although the pattern appears for 126 < Z < 135 for nuclides with neutron counts in this range.

Between ³⁸⁰Utn and ³⁷⁶Utn, two even-N isotopes, ³⁸⁰Utn and ³⁷⁸Utn are predicted to decay quickly ( < 10^-09 sec) and the others to decay by beta emission with half-lives in the 0.001 - 1 sec range. Although puzzling, nuclides with neutron counts in this range behave similarly for 126 < Z < 135.

³⁷⁵Utn is predicted to decay by fission with a half-life in the 10^-09 - 10^-06 sec range. At least this behavior is expected.

There is a gap from ³⁷⁴Utn to ³⁷⁰Utn 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.

In the band ³⁶⁹Utn to ³⁶²Utn all isotopes are predicted to decay by fission. Half-lives of even-N isotopes rise as A declines from < 10^-09 sec to the 10^-09 - 10^-06 sec range. Odd-N isotopes show greater stability, half-lives rising from the 10^-09 - 10^-06 sec range to the 0.001 - 1 sec range.

³⁶¹Utn and ³⁶⁰Utn are predicted to decay by fission with half-lives in the 0.001 - 1 sec range.

Isotopes in the band ³⁵⁹Utn to ³⁵⁷Utn are predicted to decay by alpha emission with a half-life in the 1 - 1000 sec range. Half-lives are probably near 1 sec (see p 12 of Ref. 3), although ³⁵⁸Utn may have a half-life of tens of seconds. Neutron count for ³⁵⁸Utn is 228.

Isotopes in the band ³⁵⁶Utn and ³⁵⁵Utn are predicted to decay by fission, with short half-lives (10^-09 - 0.001 sec ranges). This is somewhat unexpected, given that neutron shell closures at N = 184 and 308 produce relatively stable, alpha-decaying nuclides below the "magic" number. It is possible that a sudden change in nuclear shape is responsible.

Between ³⁵⁴Utn and ³¹⁸Utn there is a gap, which may contain short-lived isotopes or nuclear drops which decay in less than 10^-14 sec. This appears to be the instability band expected above N = 184.

³¹⁷Utn and ³¹⁶Utn are predicted to decay by fission with half-lives under 10^-06 sec.

Dominant decay branch for all isotopes in the ³¹⁵Utn to ³⁰⁵Utn band is predicted to be fission. Half-lives are comparatively long, with the odd-N isotopes ³¹³Utn, ³¹¹Utn, and ³⁰⁹Utn predicted to be in the 0.001 - 1 sec range and the others in the 10^-06 - 0.001 range. It is likely that alpha emission is a secondary decay mode, and possibly positron emission / electron capture. Neutron count for ³¹⁴Utn is 184, so this appears to reflect increased stability below a closed shell.

Odd-N isotopes in the band ³⁰⁴Utn to ²⁹⁹Utn are predicted to decay by fission with half-lives in the 10^-09 - 10^-06 sec range. Even-N isotopes presumably decay by fission, but too quickly for them to be reported in Ref. 3.

OCCURRENCE

FORMATION

Where nuclear drops between the neutron dripline and ⁴³⁹Utn 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, particularly since beta+neutrons decay is quite likely in this region. Since some of these chains may be terminated by short-lived, fission-decaying nuclides, it is not possible to say which isotopes of Utn in this range can form.

All even-N nuclear drops in the band ⁴³⁸Utn to ⁴²³Utn are predicted to be nuclides. Nearly all nuclear drops in the bands ⁴³²Utn to ³⁷⁵Utn, ³⁶⁹Utn to ³⁵⁵Utn, and ³¹⁷Utn to ³⁰⁵Utn; as well as odd-N isotopes in the band ³⁰³Utn to ²⁹⁹Utn; 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 Ref. 3 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, 61 predicted isotopes; even-N isotopes between ⁴³⁸Utn and ⁴²³Utn. all isotopes between ⁴²²Utn and ³⁷¹Utn, plus ³⁶²Utn; can form.

Neutron capture may be able to produce nuclides up to A around 360 before fission attrition stops further growth. Neutron capture can be expected to contribute to formation of isotopes between ³⁸⁰Utn and ³⁷¹Utn, plus ³⁶²Utn.

PERSISTENCE

³⁶⁴Utn and heavier isotopes will vanish within 1000 sec after a neutron star merger which led to their formation, or lie at higher Z than beta-decay chains which end in nuclides which fission with a half-life not much greater than 1 sec.

³⁶³Utn to ³⁶⁰Utn lie at higher Z than the terminations of beta-decay chains that would populate them.

³⁵⁹Utn to ³⁵⁷Utn are all predicted to have half-lives in the 1 - 1000 sec range, but are prevented from forming by alpha-decaying isotopes of Ubo.

³⁵⁶Utn is predicted to be fission-decaying, but short-lived and prevented from forming by the alpha-decaying ³⁵⁶Uto,

If lighter isotopes of Utn can form, they are not expected to persist significantly.

Calculations done under maximum half-life assumptions and with all nuclides initially populated still point to all isotopes of Utn vanishing within 10^5.5 (3.16E05) sec.

ATOMIC PROPERTIES

Utn is expected to be an 8th period active metal (superactinide). Its consensus electron configuration has been predicted to be [Og] 5g⁵ 6f³ 7d¹ 8s² 8p¹_1/2.

REFERENCES

1. 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.

2. 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.

3. "Decay Modes and a Limit of Existence of Nuclei"; H. Koura; 4th Int. Conf. on the Chemistry and Physics of Transactinide Elements; Sept. 2011.

4. "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".

5.  "Magic Numbers of Ultraheavy Nuclei"; Vitali Denisov; Physics of Atomic Nuclei; researchgate.net/publications/225734594; July 2005.

6. Other references are found in the wiki articles cited.

9-Period Periodic Table of Elements
1	1 H																																																																	2 He
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
Alkali metal Alkaline earth metal Lanthanide Actinide Superactinide Transition metal Post-transition metal Metalloid Other nonmetal Halogen Noble gas predicted predicted predicted predicted predicted predicted predicted predicted predicted

(07-23-20)