Untriquadium

Untriquadium
134Utq
- ↑ Utq ↓ Uoq Extended periodic table untritrium ← untriquadium → untripentium
Appearance
unknown
General properties
Name, symbol, number	untriquadium, Utq, 134
Pronunciation	/uːntraɪˈkwɒdiəm/
Element category	superactinides
Group, period, block	N/A, 8, g
Mass number	not applicable
Electron configuration	[Uuo] 5g86f48s28p2 (predicted) 2, 8, 18, 32, 40, 22, 8, 4 (predicted)
Physical properties
unknown
Atomic properties
unknown
Most stable isotopes
Main article: Isotopes of untriquadium
iso NA half-life DM DE (MeV) DP 356Utq (predicted) syn short-lived
v • t • e • r

Untriquadium, Utq, is the temporary name for element 134. Isotopes are predicted within the bands ⁴⁴⁴Utq to ³⁸³Utq, ³⁶⁹Utq to ³⁵⁵Utq, and ³¹⁷Utq to ³¹³Utq. There may be isotopes in the band from the neutron dripline to ⁴⁴⁵Utq, 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. Fifty-three isotopes within the bands ⁴⁴⁴Utq to ⁴²⁶Utq and ⁴²³Utq to ³⁸⁹Utq are predicted to form. All Utq 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 ⁴⁷⁷Utq to ⁴⁴⁵Utq are unlikely to decay by neutron emission and are stable enough against fission to allow beta decay. Between ⁴⁶⁷Utq and ⁴⁴⁵Utq, Ref. 3 makes no predictions, but extrapolation from higher Z indicates that it would predict some short-lived, fission-decaying nuclides. Nuclear properties above ⁴⁴⁴Utq are highly uncertain, but it is likely that some relatively long-lived, beta-decaying isotopes of Utq are possible. It is possible to state that half-lives longer than 1 sec are implausible between the neutron dripline (nominally ⁴⁷⁷Utq) and ⁴⁴⁵Utq.

PREDICTED PROPERTIES

Isotopes in the band ⁴⁴⁴Utq - ⁴³⁰Utq 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.

Isotopes in the band ⁴²⁹Utq - ⁴²⁵Utq are predicted to decay by fission. It appears to be possible for structure to destabilize a nuclide⁽⁵⁾, so the data reported appear to be realistic, Half-lives are masked by other features of the map, but half-lives of nuclides of higher Z and comparable N indicate half-lives on the order of 10^-06 to 0.001 sec. If this is the case, beta emission is an important secondary decay mode.

Isotopes in the band ⁴²⁴Utq - ⁴⁰³Utq are predicted to decay by beta emission, although a secondary fission branch is likely at the low-A end of the band. All half-lives are predicted to lie between 0.001 and 1 sec.

Most isotopes in the band ⁴⁰²Utq to ³⁹⁶Utq are predicted to decay principally by beta emission and have half-lives in the 0.001 - 1 sec range. Fission is predicted to dominate for ³⁹⁸Utq and ³⁹⁶Utq, and ³⁹⁶Utq is also predicted to have a half-life in the 10^-06 - 0.001 sec range.

In the band ³⁹⁵Utq to ³⁹⁰Utq, most species are predicted to decay principally by beta emission and have half-lives in the 0.001 - 1 sec range. ³⁹⁴Utq and ³⁹¹Utq, though are either nuclides with very short half-lives or drops too unstable to be nuclides. ³⁹¹Utq is an odd-N nuclide.

There is a gap from ³⁸⁹Utq to ³⁸⁷Utq which probably contains very short-lived, fission decaying nuclides, but may be drops too unstable to be nuclides.

Between ³⁸⁶Utq and ³⁸⁴Utq, beta-decaying isotopes with 0.001 - 1 sec half-lives are predicted. This seems odd, but is not inconsistent with lower-Z nuclides with similar neutron counts.

³⁸³Utq is predicted to decay by fission with a half-life in the 10^-09 - 10^-06 range.

There is a gap from ³⁸²Utq to ³⁷⁰Utq 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.

Between ³⁶⁹Utq and ³⁶³Utq, all isotopes are predicted to decay by fission. Half-lives rise, as A declines, from <10^-09 sec to the 0.001 - 1 sec range.

³⁶²Utq is predicted to decay by alpha emission with a half-life in the 1 - 1000 sec range. Neutron count for this isotope is 228.

In the band ³⁶¹Utq to ³⁵⁵Utq, odd-N isotopes are predicted to decay by fission with half-lives under 0.001 sec. Even-N particles are either very short-lived nuclides or unstable nuclear drops.

There is a gap from ³⁵⁴Utq to ³¹⁸Utq, in which particles are either nuclides with half-lives < 10^-09 sec or nuclear drops too short-lived to qualify as nuclides. The latter possibility is more likely.

Odd-N particles in the band ³¹⁷Utq - ³¹³Utqare predicted to decay by fission with half-lives in the 10^-09 - 10^-06 sec range. Even-N particles are either very short-lived nuclides or unstable nuclear drops.

N = 258 CLOSURE

The model used to predict decay properties of Utq 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, some isotopes in the ³⁹⁴Utq to ³⁸²Utq band may decay by beta emission rather than fission as predicted. They will probably be short-lived, but act as precursors to long-lived nuclides. By contrast, one or more isotopes in the band ³⁸¹Utq to ³⁷⁰Utq may be long lived, with half-lives exceeding 1000 sec, because they are daughters of long-lived, alpha-decaying species. 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.

OCCURRENCE

FORMATION

Where nuclear drops between the neutron dripline (nominally ⁴⁷⁷Utq) and ⁴⁴⁵Utq 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 by short-lived, fission-decaying nuclides, it is not possible to say which isotopes of Utq in this range can form.

Nearly all nuclear drops in the bands ⁴⁴⁴Utq to ³⁹⁰Utq, ³⁸⁶Utq to ³⁸³Utq, ³⁶⁹Utq to ³⁵⁵Utq, and ³¹⁷Utq to ³¹³Utq 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, 53 predicted isotopes; ⁴⁴⁴Utq to ⁴²⁶Utq, ⁴²³Utq to ³⁹¹Utq, and ³⁸⁹Utq; 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 Utq isotope. Fission infall may contribute small amounts of nuclides with A up to 406 (nominal).

PERSISTENCE

⁴⁰¹Utq 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.

⁴⁰⁰Utq to ³⁶⁴Utq lie at higher Z than the terminations of beta-decay chains that would populate them. In all cases, chains end in short-lived, fission-decaying nuclides.

³⁶³Utqto ³⁵³Utq lie at higher Z than the terminations of beta-decay chains that would populate them. Beta-decay chains end in long-lived nuclides (at lower Z), which decay by either fission or alpha emission.

If lighter isotopes of Utq 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 Utq vanishing within 10^5.5 (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 Utq isotopes may persist for up to 60 yrs, probably as a daughter of a long-lived ancestor.

ATOMIC PROPERTIES

Utq is expected to be an 8th period active metal (superactinide). Its consensus electron configuration has been predicted⁽⁶⁾ to be [Og] 5g⁸ 6f⁴ 8s² 8p²_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. "Extended Periodic Table", Wikipedia.

7. 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

(07-04-20)