Lawrencium, Lr, is the name of Z = 103. 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 in quantity.
Half-lives of Lr isotopes may range up to 11 hrs, The longer-lived isotopes may survive, in principle, long enough to become part of a supernova or kilonova (neutron star merger) diffuse remnant. However, quantities will be too small to detect, and will disappear completely within about 2 months.
While the element can form, it can only survive to reach a cool environment when synthesized in a laboratory. Its chemistry is entirely synthetic.
Per Wikipedia, Lr has the highest atomic number of any element that is made on a production basis. Production, in this sense, is measured in atoms per day.
NUCLEAR PROPERTIES
INFORMATION SOURCES
Japan Atomic Energy Agency (JAEA) maintains an on-line chart of nuclides which includes decay properties of many predicted nuclides(1) - 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 b- and b+), and alpha emission. This reference provides the most focused look at the most significant predicted Lr isotopes.
An independent resource is provided by the U.S.'s Los Alamos National Laboratory (LANL) in interactive tables of contains tabulated partial half-life data for alpha and beta decay(2) for numerous nuclides. The great weakness of this source is that it does not consider fission.
A third source describes decay properties of a large number of nuclides(3). Half-life data in this source are presented via color, which makes specifying a value within an order of magnitude difficult. In addition, only the dominant decay mode is reported. Charts on pp 11 - 13 are the most valuable part of the document.
PREDICTED PROPERTIES
Isotopes from the neutron dripline down to 275Lr are predicted to decay primarily by beta emission. Half lives increase, as A declines, from around 0.001 sec at the dripline to 1 sec near 290Lr, 100 sec around 280Lr, and peaking around 400 sec in 275Lr. Isotopes at the light end of this band are likely to decay by a mixture of beta emission and fission.
Between 274Lr and 269Lr, the predominant mode of decay is predicted to be fission, although a beta-decay branch is predicted for all isotopes except 273Lr. Half lives range from about 1.3 min in 269Lr down to 0.8 ms at 273Lr.
268Lr is predicted to decay principally via beta emission with a half-life around 20 min. Both alpha emission and fission are predicted to be secondary decay modes. Beta stability is predicted at 267Lr, so beta decay will be (b-), not (b+).
267Lr is predicted to decay principally by principally by fission, but to have an alpha-emission branch. It is not predicted to beta-decay. Its half-life is predicted to be on the order of 3.5 hrs, making it one of the longest-lived Lr isotopes.
Observation of 266Lr as a decay product of 294Ts has been reported. It's only observed decay mode was fission and its half-life computed as 11 hr. This is not inconsistent with adjacent isotopes. However, 266Lr is a minor decay branch of 270Db. Given the small number of events observed, and the presence of an uncertain alpha decay branch ratio at 270Db, both decay mode and half-life of 266Lr should be considered uncertain.
Isotopes in the band 265Lr to 263Lr have not been observed. They are all predicted to have multiple decay modes and, for Lr, long half-lives. 265Lr is predicted to decay by a relatively even mix of alpha emission and fission, with a half-life on the order of 1.5 hr. It is predicted to have a weak beta-decay branch. Since beta-stability is reported to occur at 267Lr, there is some possibility of (b-) emission, but it is likely that 265Lr may actually emit positrons (b+) or decay by electron capture (EC). 264Lr decays primarily by beta emission with a half-life on the order of 1 hr. (b-) emission is much less likely than (b+) emission or EC. 263Lr is predicted to have a half-life around 20 min, and to decay principally by alpha emission, with a significant beta-decay branch. That branch is likely to be (b+) emission.
Isotopes have been predicted or observed down to 241Lr. Between 240Lr and 232Lr, there is a gap containing nuclides with half-lives in the 10-14 - 10-09 sec range or nuclear drops too short-lived to qualify as nuclides. Decay by fission is to be expected.
Ref. 3 predicts that a set of isotopes, 231Lrto 228Lr will have half-lives exceeding 10-09 sec. They are predicted to be short-lived and to decay by proton emission.
OCCURRENCE
FORMATION
It appears likely that Lr isotopes from the neutron dripline down to 273Lr can form. Some losses due to fission in beta-decay chains leading to Lr is likely, but is not expected to cut off such chains completely.
Ref 1 indicates that even-N nuclides between 272No and 266No have no beta-decay branches. Odd-N nuclides in this band do show a minor beta decay branch, except for 267No, for which beta decay dominates. The isotopes 271Lr, 269Lr, and 267Lr can form. Refs 2 and 3 support this conclusion.
Ref. 1, indicates that nuclides in the band 265No through 262No have no beta-decay branches. This is supported by beta-decay information from Ref 2 and fission partial half-lives from Ref. 3. It appears unlikely that 265Lr to 263Lr can form.
It is unlikely that 261Lr 261 and lighter isotopes can form.
Large, neutron rich nuclides expelled from disintegrating neutron stars and large nuclides built up by rapid neutron capture in neutron star mergers and supernovae contribute to production of all Lr isotopes which can form.
PERSISTENCE
If the half-life reported for 266Lr is accurate, it is the longest-lived Lr isotope by a considerable margin. It can, therefore be expected to persist, in principle, for perhaps 2 months after a supernova, neutron star merger, or other event leading to its formation. Of the remaining isotopes, 267Lr is second-longest lived with a half-life around 3.5 hrs, and persistence of less than a month. Other isotopes are expected to persist for shorter times.
Theoretically, some Lr may exist in very young supernova or kilonova (neutron star merger) remnants, but will not be present in detectable quantities.
ATOMIC PROPERTIES
Wikipedia's article "Lawrencium" addresses the element's atomic properties and chemistry in some detail. It is unlikely that any Lr can survive, outside the laboratory, to reach an environment cool enough for chemical interactions to occur.
REFERENCES
1. "Chart of the Nuclides, 2014", Japan Atomic Energy Agency; website available using "chart of nuclides" and "JAEA" as internet search terms.
2. "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".
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. "Isotopes of Lawrencium", Wikipedia article.
(11-15-20)
| 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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