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The alkaline earth metal strontium (38 Sr) has four stable, naturally occurring isotopes: 84 Sr (0.56%), 86 Sr (9.86%), 87 Sr (7.0%) and 88 Sr (82.58%). Its standard atomic weight is 87.62(1). Only 87 Sr is radiogenic ; it is produced by decay from the radioactive alkali metal 87 Rb , which has a half-life of 4.88 × 10 10 years (i.e. more than ...
Natural strontium is a mixture of four stable isotopes: 84 Sr, 86 Sr, 87 Sr, and 88 Sr. [11] On these isotopes, 88 Sr is the most abundant, makes up about 82.6% of all natural strontium, though the abundance varies due to the production of radiogenic 87 Sr as the daughter of long-lived beta-decaying 87 Rb. [22]
38 Al 39 Si 26 37 Na 38 Mg 39 Al 40 Si 27 40 Al 41 Si 28 39 Na 40 Mg 41 Al 42 Si 29 ... 84 Sr 85 Y 86 Zr 87 Nb 88 Mo 89 Tc 90 Ru 47 77 Zn. 78 Ga 79 Ge. 80 As 81 Se ...
Rb–Sr dating relies on correctly measuring the Rb–Sr ratio of a mineral or whole rock sample, plus deriving an accurate 87 Sr/ 86 Sr ratio for the mineral or whole rock sample. Several preconditions must be satisfied before a Rb–Sr date can be considered as representing the time of emplacement or formation of a rock.
4: Each atom has four near neighbours, 2 at 275.4 pm, 2 at 285.4 pm. The next four at distances 326.3 pm and four more at 334.2 pm. [17] Strongly distorted hcp structure. α-Ga: A11: Orthorhombic: Cmce (No. 64) 8: each Ga atom has one nearest neighbour at 244 pm, 2 at 270 pm, 2 at 273 pm, 2 at 279 pm. [18] The structure is related to that of ...
Naturally occurring strontium is nonradioactive and nontoxic at levels normally found in the environment, but 90 Sr is a radiation hazard. [4] 90 Sr undergoes β − decay with a half-life of 28.79 years and a decay energy of 0.546 MeV distributed to an electron, an antineutrino, and the yttrium isotope 90 Y, which in turn undergoes β − decay with a half-life of 64 hours and a decay energy ...
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They considered elements 158 through 164 to be homologues of groups 4 through 10, and not 6 through 12, noting similarities of electron configurations to the period 5 transition metals (e.g. element 159 7d 4 9s 1 vs Nb 4d 4 5s 1, element 160 7d 5 9s 1 vs Mo 4d 5 5s 1, element 162 7d 7 9s 1 vs Ru 4d 7 5s 1, element 163 7d 8 9s 1 vs Rh 4d 8 5s 1 ...