

A368856


Atomic numbers with at least two betastable isotopes of odd mass number.


1



2, 17, 19, 22, 29, 31, 35, 42, 44, 47, 50, 51, 54, 56, 60, 62, 63, 64, 66, 70, 72, 76, 77, 80, 81, 84, 88, 90, 92, 95, 98, 100
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OFFSET

1,1


COMMENTS

A betastable nuclide is a nuclide whose beta decay (betaminus and betaplus decay) is energetically disallowed; that is to say, a nuclide that has lower energy than its isobars with one more or one less proton. Note that double beta decay is allowed. A nuclide whose beta decay is energetially allowed, even if not observed (in the case of 48Ca, 96Zr, 123Te, 148Gd, 180mTa, 222Rn and 247Cm), is not classified as being betastable.
For n <= 101 not being a term in this sequence, there is only one oddmass betastable isotope for element n, except that there is none for n = 18, 43, 58 and 61.
2 is a term because even if 5He has extremely short halflife, it is betastable. 48, 49 and 52 are not terms because 113Cd, 115In and 123Te are not betastable as primordial nuclides.
Different models predict different continuations for this sequence: Page 12 of the Zagrebaev et al. link predicts 101, (3 numbers in 105 ~ 108, assuming Lr and Mt each have a betastable isotopes and Sg, Bh and Hs each have at most two betastable isotopes of odd mass number), 110, 112, 114 (page 12). A Russian source predicts 102, 104, 105 or 106, 110, 112, 114, 116, 118. Pages 1415 of the Hiroyuki Koura link predict 101, 102, 104, 106, 108, 110, 113, 116, 117, 118, 120, 122, 124 (pages 1415).
In contrast to many terms being known for this sequence, there are only four known neutron numbers with two betastable isotones of odd mass number: 20 (37Cl and 39K), 55 (97Mo and 99Ru), 82 (139La and 141Pr) and 85 (145Nd and 147Sm). The two even neutron numbers are close to the elements Ar and Ce which have only eveneven betastable isotopes, and the two odd ones surround the elements Tc and Pm which have no betastable isotopes. The Zagrebaev et al. link predicts two betastable isotones with neutron number 181 (293Cn and 295Fl), with Nh having no betastable isotopes.


LINKS



EXAMPLE

Z = 2: 3He and 5He;
Z = 17: 35Cl and 37Cl;
Z = 19: 39K and 41K;
Z = 22: 47Ti and 49Ti;
Z = 29: 63Cu and 65Cu;
Z = 31: 69Ga and 71Ga;
Z = 35: 79Br and 81Br;
Z = 42: 95Mo and 97Mo;
Z = 44: 99Ru and 101Ru;
Z = 47: 109Ag and 111Ag;
Z = 50: 115Sn, 117Sn and 119Sn;
Z = 51: 121Sb and 123Sb;
Z = 54: 129Xe and 131Xe;
Z = 56: 135Ba and 137Ba;
Z = 60: 143Nd and 145Nd;
Z = 62: 147Sm and 149Sm;
Z = 63: 151Eu and 153Eu;
Z = 64: 155Gd and 157Gd;
Z = 66: 161Dy and 163Dy;
Z = 70: 171Yb and 173Yb;
Z = 72: 177Hf and 179Hf;
Z = 76: 187Os and 189Os;
Z = 77: 191Ir and 193Ir;
Z = 80: 199Hg and 201Hg;
Z = 81: 203Tl and 205Tl;
Z = 84: 211Po and 213Po;
Z = 88: 221Ra and 223Ra;
Z = 90: 227Th and 229Th;
Z = 92: 233U and 235U;
Z = 95: 241Am and 243Am;
Z = 98: 249Cf and 251Cf;
Z = 100: 255Fm and 257Fm.
Note that 5He and nuclides with mass number > 209 (except for 235U) are nonprimordial in this list.


CROSSREFS



KEYWORD

nonn,fini,hard,more


AUTHOR



STATUS

approved



