Flerovium

Flerovium (Fl) is the name of element 114. Wikipedia has an article which provides a lot of information about the element.  This article will focus on things Wikipedia does not stress: heavy isotopes and formation.

The longest lived Fl isotopes are predicted to lie in the band from ²⁹⁸Fl to ²⁹²Fl. Peak half-life is predicted to be over 10 days. Those isotopes cannot form. Longest half-lives for isotopes which can form, all of which are heavier than ³¹²Fl, are predicted to be under a second. Any Fl which does form will disappear within 10¹² (a trillion) years of the event which led to its formation. This means that the element will be in an environment cool enough for it to interact chemically.

Nuclear properties

Information sources

This article uses two main resources chosen because of their independence from one another. A third source provides quantitative data over a limited range.

At least one document maps half-life and decay mode for elements below Z = 175 from the neutron dripline down to isotopes which are too neutron-poor to survive any appreciable length of time. Maps on pp 15 & 18 address the entire (Z,N) region covered, but report only the dominant decay mode and report half-lives only to within a band three orders of magnitude wide (0.001 - 1 sec, for example). More detailed estimates of these properties can be extracted from maps on pp 11 & 12, but only for a limited range of Z and N. Half-life data are reported by colors, which makes numerical estimates laborious to produce. This document is connected to Japan's KTUY model.

An independent map of half-lives and decay modes exists. This one is limited to A = 339, as well as to Z = 132. It does not show short-lived isotopes well, and gives half-lives only within rather broad and awkward bands. It does show multiple decay modes for single nuclides. It originates from models used by the Russian agency JINR, so is completely independent of .

Japan Atomic Energy Agency (JAEA) maintains an on-line chart of nuclides which includes decay properties of many predicted nuclides - unlike charts published by Korea Atomic Energy Research Institute (KAERI) or the (U.S.) National Nuclear Data Center (NNDC). This chart gives separate numerical values for partial half-lives against fission, beta emission (both β^- and β⁺), and alpha emission. These appear to be systematically too long, but are probably reliable to within an order of magnitude.

Predicted properties

Even-N isotopes from the neutron dripline down to ³⁵⁷Fl are predicted to have half-lives in the 0.001 - 1 sec range. (Half-lives aren't reported directly, but the properties of beta decay indicate that half-lives close to 0.001 sec are likely.) In some cases, fission is predicted to be the dominant decay mode, but both fission and beta emission are likely to be significant modes for all isotopes. Odd-N drops in this band decay by neutron emission.

Isotopes in the band ³⁵⁶Fl to ³²³Fl are predicted to decay by beta emission, with two exceptions. All are predicted to have half-lives in the 0.001 - 1 sec range. The two exceptions, ³³⁰Fl and ³²⁴Fl have a dominant fission decay mode. Both beta emission and fission are likely to be important in all isotopes, at least at the lower end of this band.

Fission is predicted to become the principal decay mode in the ³²²Fl to ³¹⁵Fl band. Half lives are predicted to show a pronounced difference between odd-N and even-N isotopes, and also to decline as A decreases. Heavier odd-N isotopes are predicted to have half-lives exceeding 1 sec, declining to the 10^-6 - 0.001 sec range at the band's low-A end. Even-N isotopes are predicted to decay more quickly.

predicts a gap from ³¹⁴Fl to ³⁰⁶Fl, All isotopes in this band have half-lives under 10^-9 sec, and most may not even survive the 10^-14 sec needed to qualify as nuclides. predicts all will have half-lives under 10^-6, which is as short a time as that document reports. Fission is the predicted decay mode in both cases.

The band ³⁰⁵Fl to ³⁰³Fl is a transition region which contains significant differences between the predictions of & , and those of . The former predict a rapid rise in half-life as A declines, and a transition to alpha emission as the dominant mode of decay at ³⁰³Fl indicating increased stability with respect to fission near N = 184. predicts that fission will dominate throughout the band, and that half-lives will be shorter

Below ³⁰³Fl, there have been many studies of decay properties. There does seem to be consensus that fission will not be a significant decay mode, that half-lives will peak just below ³⁰⁰Fl, and that fairly long half-lives will be possible near N = 184. predicts that three alpha-decaying isotopes, ²⁹⁸Fl, ²⁹⁷Fl, and ²⁹⁶Fl will have half-lives exceeding 10 days, and that two others, ²⁹³Fl and ²⁹²Fl will have half-lives exceeding 1 day. Positive beta (b⁺ / EC) and alpha are predicted to be about equally important in ²⁹³Fl. Further comparison of predicted decay properties or evaluation of likely actual properties is out of scope for this article.

Observed half-lives are found in the band ²⁹⁰Fl to ²⁸⁴Fl. The lighter isotopes have half-lives comparable to the half-lives of adjacent isotopes, as predicted in , but ²⁸⁹Fl has an observed half-life around 0.02 times the predicted half-lives for ²⁹⁰Fl and ²⁹¹Fl. In addition, there is an unconfirmed report that ²⁹⁰Fl has been observed and has a half-life of 19 sec.

The lightest isotope reported by any of , or is ²⁷³Fl. There may be a few lighter nuclides with half-lives in the 10^-14 - 10^-9 sec range, but half-lives will quickly decline below the minimum needed for a nuclear drop to qualify as a nuclide.

Occurence

Formation

Flerovium isotopes exist between the neutron dripline and ³¹⁹Fl most decay mainly by beta emission; but some, particularly at the light end of the band, decay mainly by fission. All are short-lived. Between ³¹⁸Fl and ²⁹⁴Fl, beta decay chains end in fission at Z < 114. This band includes relatively long-lived nuclides stabilized by the N = 184 neutron shell closure. Below ²⁹⁴Fl, beta decay chains end in alpha decaying nuclides, but at Z < 114. Material ejected from a disintegrating neutron star is expected to cover the entire A range over which Fl isotopes can form. See Superheavy Island is Deserted for more information.

Neutron capture may be able to produce nuclides up to A around 380 before fission attrition stops further growth. Neutron capture is expected to contribute to formation of almost all Fl isotopes.

Persistence

All Fl isotopes which can form have short half-lives and are the result of beta decay of short-lived nuclides. The element is expected to disappear completely less than 1000 sec after a neutron star merger of similar event which led to its formation.

Atomic properties

Wikipedia's article "Flerovium" addresses the element's atomic properties and chemistry in some detail. One point it does not make is that, while Fl nuclei can form, they do not persist long enough to reach an environment cool enough to allow chemical processes. The chemistry of Fl is entirely synthetic.

References

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

(10-10-20)