Rubidium Rubidium is the chemical element with the symbol Rb and atomic number 37. It is a very soft, whitish-grey solid in the alkali metal group, similar to potassium and caesium. Rubidium is the first alkali metal in the group to have a density hig ...

(₃₇Rb) has 36

isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers ( mass number ...

s, with naturally occurring rubidium being composed of just two isotopes; ⁸⁵Rb (72.2%) and the

radioactive Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is consi ...

⁸⁷Rb (27.8%). Normal mixes of rubidium are radioactive enough to fog photographic film in approximately 30 to 60 days. ⁸⁷Rb has a

half-life Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable at ...

of . It readily substitutes for

potassium Potassium is the chemical element with the symbol K (from Neo-Latin '' kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosp ...

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ...

s, and is therefore fairly widespread. ⁸⁷Rb has been used extensively in dating rocks; ⁸⁷Rb decays to stable

strontium Strontium is the chemical element with the symbol Sr and atomic number 38. An alkaline earth metal, strontium is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is ...

-87 by emission of a

beta particle A beta particle, also called beta ray or beta radiation (symbol β), is a high-energy, high-speed electron or positron emitted by the radioactive decay of an atomic nucleus during the process of beta decay. There are two forms of beta decay, β� ...

(an electron ejected from the nucleus). During

fractional crystallization Fractional crystallization may refer to: * Fractional crystallization (chemistry), a process to separate different solutes from a solution * Fractional crystallization (geology) Fractional crystallization, or crystal fractionation, is one of the ...

, Sr tends to become concentrated in

plagioclase Plagioclase is a series of tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continuous solid solution series, more pro ...

, leaving Rb in the liquid phase. Hence, the Rb/Sr ratio in residual

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natura ...

may increase over time, resulting in rocks with increasing Rb/Sr ratios with increasing

differentiation Differentiation may refer to: Business * Differentiation (economics), the process of making a product different from other similar products * Product differentiation, in marketing * Differentiated service, a service that varies with the identity ...

. The highest ratios (10 or higher) occur in

pegmatite A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than and sometimes greater than . Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic co ...

s. If the initial amount of Sr is known or can be extrapolated, the age can be determined by measurement of the Rb and Sr concentrations and the ⁸⁷Sr/⁸⁶Sr ratio. The dates indicate the true age of the minerals only if the rocks have not been subsequently altered. See

rubidium–strontium dating The rubidium-strontium dating method is a radiometric dating technique, used by scientists to determine the age of rocks and minerals from their content of specific isotopes of rubidium (87Rb) and strontium (87Sr, 86Sr). One of the two naturally ...

for a more detailed discussion. Other than ⁸⁷Rb, the longest-lived

radioisotope A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferr ...

s are ⁸³Rb with a half-life of 86.2 days, ⁸⁴Rb with a half-life of 33.1 days, and ⁸⁶Rb with a half-life of 18.642 days. All other radioisotopes have half-lives less than a day. ⁸²Rb is used in some

cardiac The heart is a muscular organ found in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon di ...

positron emission tomography Positron emission tomography (PET) is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in metabolic processes, and in other physiological activities including blood flow, ...

scans to assess myocardial perfusion. It has a

of 1.273 minutes. It does not exist naturally, but can be made from the decay of ⁸²Sr.

List of isotopes

, - , ⁷¹Rb , style="text-align:right" , 37 , style="text-align:right" , 34 , 70.96532(54)# , , p , ⁷⁰Kr , 5/2−# , , , - , ⁷²Rb , style="text-align:right" , 37 , style="text-align:right" , 35 , 71.95908(54)# , <1.5 μs , p , ⁷¹Kr , 3+# , , , - , style="text-indent:1em" , ^72mRb , colspan="3" style="text-indent:2em" , 100(100)# keV , 1# μs , p , ⁷¹Kr , 1−# , , , - , ⁷³Rb , style="text-align:right" , 37 , style="text-align:right" , 36 , 72.95056(16)# , <30 ns , p , ⁷²Kr , 3/2−# , , , - , ⁷⁴Rb , style="text-align:right" , 37 , style="text-align:right" , 37 , 73.944265(4) , 64.76(3) ms , β⁺ , ⁷⁴Kr , (0+) , , , - , ⁷⁵Rb , style="text-align:right" , 37 , style="text-align:right" , 38 , 74.938570(8) , 19.0(12) s , β⁺ , ⁷⁵Kr , (3/2−) , , , - , rowspan=2, ⁷⁶Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 39 , rowspan=2, 75.9350722(20) , rowspan=2, 36.5(6) s , β⁺ , ⁷⁶Kr , rowspan=2, 1(−) , rowspan=2, , rowspan=2, , - , β⁺, α (3.8×10⁻⁷%) , ⁷²Se , - , style="text-indent:1em" , ^76mRb , colspan="3" style="text-indent:2em" , 316.93(8) keV , 3.050(7) μs , , , (4+) , , , - , ⁷⁷Rb , style="text-align:right" , 37 , style="text-align:right" , 40 , 76.930408(8) , 3.77(4) min , β⁺ , ⁷⁷Kr , 3/2− , , , - , ⁷⁸Rb , style="text-align:right" , 37 , style="text-align:right" , 41 , 77.928141(8) , 17.66(8) min , β⁺ , ''⁷⁸Kr'' , 0(+) , , , - , rowspan=2 style="text-indent:1em" , ^78mRb , rowspan=2 colspan="3" style="text-indent:2em" , 111.20(10) keV , rowspan=2, 5.74(5) min , β⁺ (90%) , ''⁷⁸Kr'' , rowspan=2, 4(−) , rowspan=2, , rowspan=2, , - , IT (10%) , ⁷⁸Rb , - , ⁷⁹Rb , style="text-align:right" , 37 , style="text-align:right" , 42 , 78.923989(6) , 22.9(5) min , β⁺ , ⁷⁹Kr , 5/2+ , , , - , ⁸⁰Rb , style="text-align:right" , 37 , style="text-align:right" , 43 , 79.922519(7) , 33.4(7) s , β⁺ , ⁸⁰Kr , 1+ , , , - , style="text-indent:1em" , ^80mRb , colspan="3" style="text-indent:2em" , 494.4(5) keV , 1.6(2) μs , , , 6+ , , , - , ⁸¹Rb , style="text-align:right" , 37 , style="text-align:right" , 44 , 80.918996(6) , 4.570(4) h , β⁺ , ⁸¹Kr , 3/2− , , , - , rowspan=2 style="text-indent:1em" , ^81mRb , rowspan=2 colspan="3" style="text-indent:2em" , 86.31(7) keV , rowspan=2, 30.5(3) min , IT (97.6%) , ⁸¹Rb , rowspan=2, 9/2+ , rowspan=2, , rowspan=2, , - , β⁺ (2.4%) , ⁸¹Kr , - , ⁸² Rb , style="text-align:right" , 37 , style="text-align:right" , 45 , 81.9182086(30) , 1.273(2) min , β⁺ , ⁸²Kr , 1+ , , , - , rowspan=2 style="text-indent:1em" , ^82mRb , rowspan=2 colspan="3" style="text-indent:2em" , 69.0(15) keV , rowspan=2, 6.472(5) h , β⁺ (99.67%) , ⁸²Kr , rowspan=2, 5− , rowspan=2, , rowspan=2, , - , IT (.33%) , ⁸²Rb , - , ⁸³Rb , style="text-align:right" , 37 , style="text-align:right" , 46 , 82.915110(6) , 86.2(1) d , EC , ⁸³Kr , 5/2− , , , - , style="text-indent:1em" , ^83mRb , colspan="3" style="text-indent:2em" , 42.11(4) keV , 7.8(7) ms , IT , ⁸³Rb , 9/2+ , , , - , rowspan=2, ⁸⁴Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 47 , rowspan=2, 83.914385(3) , rowspan=2, 33.1(1) d , β⁺ (96.2%) , ⁸⁴Kr , rowspan=2, 2− , rowspan=2, , rowspan=2, , - , β⁻ (3.8%) , ⁸⁴Sr , - , rowspan=2 style="text-indent:1em" , ^84mRb , rowspan=2 colspan="3" style="text-indent:2em" , 463.62(9) keV , rowspan=2, 20.26(4) min , IT (>99.9%) , ⁸⁴Rb , rowspan=2, 6− , rowspan=2, , rowspan=2, , - , β⁺ (<.1%) , ⁸⁴Kr , - , ⁸⁵Rb

Fission product Nuclear fission products are the atomic fragments left after a large atomic nucleus undergoes nuclear fission. Typically, a large nucleus like that of uranium fissions by splitting into two smaller nuclei, along with a few neutrons, the release ...

, style="text-align:right" , 37 , style="text-align:right" , 48 , 84.911789738(12) , colspan=3 align=center, Stable , 5/2− , 0.7217(2) , , - , rowspan=2, ⁸⁶Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 49 , rowspan=2, 85.91116742(21) , rowspan=2, 18.642(18) d , β⁻ (99.9948%) , ⁸⁶Sr , rowspan=2, 2− , rowspan=2, , rowspan=2, , - , EC (.0052%) , ⁸⁶Kr , - , style="text-indent:1em" , ^86mRb , colspan="3" style="text-indent:2em" , 556.05(18) keV , 1.017(3) min , IT , ⁸⁶Rb , 6− , , , - , ⁸⁷Rb

Primordial Primordial may refer to: * Primordial era, an era after the Big Bang. See Chronology of the universe * Primordial sea (a.k.a. primordial ocean, ooze or soup). See Abiogenesis * Primordial nuclide, nuclides, a few radioactive, that formed before ...

radionuclide A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transfer ...

Used in

, style="text-align:right" , 37 , style="text-align:right" , 50 , 86.909180527(13) , 4.923(22)×10¹⁰ y , β⁻ , ⁸⁷Sr , 3/2− , 0.2783(2) , , - , ⁸⁸Rb , style="text-align:right" , 37 , style="text-align:right" , 51 , 87.91131559(17) , 17.773(11) min , β⁻ , ⁸⁸Sr , 2− , , , - , ⁸⁹Rb , style="text-align:right" , 37 , style="text-align:right" , 52 , 88.912278(6) , 15.15(12) min , β⁻ , ⁸⁹Sr , 3/2− , , , - , ⁹⁰Rb , style="text-align:right" , 37 , style="text-align:right" , 53 , 89.914802(7) , 158(5) s , β⁻ , ⁹⁰Sr , 0− , , , - , rowspan=2 style="text-indent:1em" , ^90mRb , rowspan=2 colspan="3" style="text-indent:2em" , 106.90(3) keV , rowspan=2, 258(4) s , β⁻ (97.4%) , ⁹⁰Sr , rowspan=2, 3− , rowspan=2, , rowspan=2, , - , IT (2.6%) , ⁹⁰ Rb , - , ⁹¹Rb , style="text-align:right" , 37 , style="text-align:right" , 54 , 90.916537(9) , 58.4(4) s , β⁻ , ⁹¹Sr , 3/2(−) , , , - , rowspan=2, ⁹²Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 55 , rowspan=2, 91.919729(7) , rowspan=2, 4.492(20) s , β⁻ (99.98%) , ⁹²Sr , rowspan=2, 0− , rowspan=2, , rowspan=2, , - , β⁻, n (.0107%) , ⁹¹Sr , - , rowspan=2, ⁹³Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 56 , rowspan=2, 92.922042(8) , rowspan=2, 5.84(2) s , β⁻ (98.65%) , ⁹³Sr , rowspan=2, 5/2− , rowspan=2, , rowspan=2, , - , β⁻, n (1.35%) , ⁹²Sr , - , style="text-indent:1em" , ^93mRb , colspan="3" style="text-indent:2em" , 253.38(3) keV , 57(15) μs , , , (3/2−,5/2−) , , , - , rowspan=2, ⁹⁴Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 57 , rowspan=2, 93.926405(9) , rowspan=2, 2.702(5) s , β⁻ (89.99%) , ⁹⁴Sr , rowspan=2, 3(−) , rowspan=2, , rowspan=2, , - , β⁻, n (10.01%) , ⁹³Sr , - , rowspan=2, ⁹⁵Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 58 , rowspan=2, 94.929303(23) , rowspan=2, 377.5(8) ms , β⁻ (91.27%) , ⁹⁵Sr , rowspan=2, 5/2− , rowspan=2, , rowspan=2, , - , β⁻, n (8.73%) , ⁹⁴Sr , - , rowspan=2, ⁹⁶Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 59 , rowspan=2, 95.93427(3) , rowspan=2, 202.8(33) ms , β⁻ (86.6%) , ⁹⁶Sr , rowspan=2, 2+ , rowspan=2, , rowspan=2, , - , β⁻, n (13.4%) , ⁹⁵Sr , - , rowspan=3 style="text-indent:1em" , ^96mRb , rowspan=3 colspan="3" style="text-indent:2em" , 0(200)# keV , rowspan=3, 200# ms 1 ms, β⁻ , ⁹⁶Sr , rowspan=3, 1(−#) , rowspan=3, , rowspan=3, , - , IT , ⁹⁶Rb , - , β⁻, n , ⁹⁵Sr , - , rowspan=2, ⁹⁷Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 60 , rowspan=2, 96.93735(3) , rowspan=2, 169.9(7) ms , β⁻ (74.3%) , ⁹⁷Sr , rowspan=2, 3/2+ , rowspan=2, , rowspan=2, , - , β⁻, n (25.7%) , ⁹⁶Sr , - , rowspan=3, ⁹⁸Rb , rowspan=3 style="text-align:right" , 37 , rowspan=3 style="text-align:right" , 61 , rowspan=3, 97.94179(5) , rowspan=3, 114(5) ms , β⁻(86.14%) , ⁹⁸Sr , rowspan=3, (0,1)(−#) , rowspan=3, , rowspan=3, , - , β⁻, n (13.8%) , ⁹⁷Sr , - , β⁻, 2n (.051%) , ⁹⁶Sr , - , style="text-indent:1em" , ^98mRb , colspan="3" style="text-indent:2em" , 290(130) keV , 96(3) ms , β⁻ , ⁹⁷Sr , (3,4)(+#) , , , - , rowspan=2, ⁹⁹Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 62 , rowspan=2, 98.94538(13) , rowspan=2, 50.3(7) ms , β⁻ (84.1%) , ⁹⁹Sr , rowspan=2, (5/2+) , rowspan=2, , rowspan=2, , - , β⁻, n (15.9%) , ⁹⁸Sr , - , rowspan=3, ¹⁰⁰Rb , rowspan=3 style="text-align:right" , 37 , rowspan=3 style="text-align:right" , 63 , rowspan=3, 99.94987(32)# , rowspan=3, 51(8) ms , β⁻ (94.25%) , ¹⁰⁰Sr , rowspan=3, (3+) , rowspan=3, , rowspan=3, , - , β⁻, n (5.6%) , ⁹⁹Sr , - , β⁻, 2n (.15%) , ⁹⁸Sr , - , rowspan=2, ¹⁰¹Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 64 , rowspan=2, 100.95320(18) , rowspan=2, 32(5) ms , β⁻ (69%) , ¹⁰¹Sr , rowspan=2, (3/2+)# , rowspan=2, , rowspan=2, , - , β⁻, n (31%) , ¹⁰⁰Sr , - , rowspan=2, ¹⁰²Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 65 , rowspan=2, 101.95887(54)# , rowspan=2, 37(5) ms , β⁻ (82%) , ¹⁰²Sr , rowspan=2, , rowspan=2, , rowspan=2, , - , β⁻, n (18%) , ¹⁰¹Sr , - , ¹⁰³Rb , style="text-align:right" , 37 , style="text-align:right" , 66 , , 26 ms , β⁻ , ¹⁰³Sr , , , , - , ¹⁰⁴Rb , style="text-align:right" , 37 , style="text-align:right" , 67 , , 35# ms (>550 ns) , β⁻? , ¹⁰⁴Sr , , , , - , ¹⁰⁵Rb , style="text-align:right" , 37 , style="text-align:right" , 68 , , , , , , , , - , ¹⁰⁶Rb , style="text-align:right" , 37 , style="text-align:right" , 69 , , , , , , ,

Rubidium-87

Rubidium-87 is an

rubidium Rubidium is the chemical element with the symbol Rb and atomic number 37. It is a very soft, whitish-grey solid in the alkali metal group, similar to potassium and caesium. Rubidium is the first alkali metal in the group to have a density hig ...

. Rubidium-87 was the first and the most popular atom for making

Bose–Einstein condensate In condensed matter physics, a Bose–Einstein condensate (BEC) is a state of matter that is typically formed when a gas of bosons at very low densities is cooled to temperatures very close to absolute zero (−273.15 °C or −459.67&n ...

s in dilute

atomic gas Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), o ...

es. Even though rubidium-85 is more abundant, rubidium-87 has a positive scattering length, which means it is mutually repulsive, at low temperatures. This prevents a collapse of all but the smallest condensates. It is also easy to evaporatively cool, with a consistent strong mutual scattering. There is also a strong supply of cheap uncoated

diode laser The laser diode chip removed and placed on the eye of a needle for scale A laser diode (LD, also injection laser diode or ILD, or diode laser) is a semiconductor device similar to a light-emitting diode in which a diode pumped directly with e ...

s typically used in CD writers, which can operate at the correct wavelength. Rubidium-87 has an atomic mass of 86.9091835 u, and a binding energy of 757,853 keV. Its atomic percent abundance is 27.835%, and has a half-life of .

References

* Isotope masses from: ** * Isotopic compositions and standard atomic masses from: ** ** * Half-life, spin, and isomer data selected from the following sources. ** ** ** {{Navbox element isotopes Rubidium