Rubidium Rubidium is a chemical element; it has Symbol (chemistry), 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 ...

(₃₇Rb) has 36

isotope Isotopes are distinct nuclear species (or ''nuclides'') of the same chemical element. They have the same atomic number (number of protons in their Atomic nucleus, nuclei) and position in the periodic table (and hence belong to the same chemica ...

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 conside ...

⁸⁷Rb (27.8%). ⁸⁷Rb has a

half-life Half-life is a mathematical and scientific description of exponential or gradual decay. Half-life, half life or halflife may also refer to: Film * Half-Life (film), ''Half-Life'' (film), a 2008 independent film by Jennifer Phang * ''Half Life: ...

of . It readily substitutes for

potassium Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...

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

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

-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, known as beta decay. There are two forms of beta decay, β− decay and � ...

(an electron ejected from the nucleus). During fractional crystallization, Sr tends to become concentrated in

plagioclase Plagioclase ( ) is a series of Silicate minerals#Tectosilicates, tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continu ...

, 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 (sometimes colloquially but incorrectly referred to as ''lava'') is found beneath the surface of the Earth, and evidence of magmatism has also ...

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

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 (Rb–Sr) 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 t ...

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 numbers of either neutrons or protons, giving it excess nuclear energy, and making it unstable. This excess energy can be used in one of three ...

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 humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrients to the tissu ...

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, r ...

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

, -id=Rubidium-72 , ⁷²Rb , style="text-align:right" , 37 , style="text-align:right" , 35 , 71.95885(54)# , 103(22) ns , p , ⁷¹Kr , 1+# , , , -id=Rubidium-73 , ⁷³Rb , style="text-align:right" , 37 , style="text-align:right" , 36 , 72.950605(44) , <81 ns , p , ⁷²Kr , 3/2−# , , , -id=Rubidium-74 , ⁷⁴Rb , style="text-align:right" , 37 , style="text-align:right" , 37 , 73.9442659(32) , 64.78(3) ms , β⁺ , ⁷⁴Kr , 0+ , , , -id=Rubidium-75 , ⁷⁵Rb , style="text-align:right" , 37 , style="text-align:right" , 38 , 74.9385732(13) , 19.0(12) s , β⁺ , ⁷⁵Kr , 3/2− , , , -id=Rubidium-76 , rowspan=2, ⁷⁶Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 39 , rowspan=2, 75.9350730(10) , rowspan=2, 36.5(6) s , β⁺ , ⁷⁶Kr , rowspan=2, 1− , rowspan=2, , rowspan=2, , - , β⁺, α (3.8×10⁻⁷%) , ⁷²Se , -id=Rubidium-76m , style="text-indent:1em" , ^76mRb , colspan="3" style="text-indent:2em" , 316.93(8) keV , 3.050(7) μs , IT , ⁷⁶Rb , (4+) , , , -id=Rubidium-77 , ⁷⁷Rb , style="text-align:right" , 37 , style="text-align:right" , 40 , 76.9304016(14) , 3.78(4) min , β⁺ , ⁷⁷Kr , 3/2− , , , -id=Rubidium-78 , ⁷⁸Rb , style="text-align:right" , 37 , style="text-align:right" , 41 , 77.9281419(35) , 17.66(3) min , β⁺ , ''⁷⁸Kr'' , 0+ , , , -id=Rubidium-78m1 , style="text-indent:1em" , ^78m1Rb , colspan="3" style="text-indent:2em" , 46.84(14) keV , 910(40) ns , IT , ⁷⁸Rb , (1−) , , , -id=Rubidium-78m2 , rowspan=2 style="text-indent:1em" , ^78m2Rb , rowspan=2 colspan="3" style="text-indent:2em" , 111.19(22) keV , rowspan=2, 5.74(3) min , β⁺ (91%) , ''⁷⁸Kr'' , rowspan=2, 4− , rowspan=2, , rowspan=2, , - , IT (9%) , ⁷⁸Rb , -id=Rubidium-79 , ⁷⁹Rb , style="text-align:right" , 37 , style="text-align:right" , 42 , 78.9239901(21) , 22.9(5) min , β⁺ , ⁷⁹Kr , 5/2+ , , , -id=Rubidium-80 , ⁸⁰Rb , style="text-align:right" , 37 , style="text-align:right" , 43 , 79.9225164(20) , 33.4(7) s , β⁺ , ⁸⁰Kr , 1+ , , , -id=Rubidium-80m , style="text-indent:1em" , ^80mRb , colspan="3" style="text-indent:2em" , 493.9(5) keV , 1.63(4) μs , IT , ⁸⁰Rb , (6+) , , , -id=Rubidium-81 , ⁸¹Rb , style="text-align:right" , 37 , style="text-align:right" , 44 , 80.9189939(53) , 4.572(4) h , β⁺ , ⁸¹Kr , 3/2− , , , -id=Rubidium-81m , 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 , 81.9182090(32) , 1.2575(2) min , β⁺ , ⁸²Kr , 1+ , , , -id=Rubidium-82m , rowspan=2 style="text-indent:1em" , ^82mRb , rowspan=2 colspan="3" style="text-indent:2em" , 69.0(15) keV , rowspan=2, 6.472(6) h , β⁺ (>99.67%) , ⁸²Kr , rowspan=2, 5− , rowspan=2, , rowspan=2, , - , IT (<0.33%) , ⁸²Rb , -id=Rubidium-83 , ⁸³Rb , style="text-align:right" , 37 , style="text-align:right" , 46 , 82.9151142(25) , 86.2(1) d , EC , ⁸³Kr , 5/2− , , , -id=Rubidium-83m , style="text-indent:1em" , ^83mRb , colspan="3" style="text-indent:2em" , 42.0780(20) keV , 7.8(7) ms , IT , ⁸³Rb , 9/2+ , , , -id=Rubidium-84 , rowspan=2, ⁸⁴Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 47 , rowspan=2, 83.9143752(24) , rowspan=2, 32.8(07) d , β⁺ (96.1%) , ⁸⁴Kr , rowspan=2, 2− , rowspan=2, , rowspan=2, , - , β⁻ (3.9%) , ⁸⁴Sr , -id=Rubidium-84m , rowspan=2 style="text-indent:1em" , ^84mRb , rowspan=2 colspan="3" style="text-indent:2em" , 463.59(8) keV , rowspan=2, 20.26(4) min , IT , ⁸⁴Rb , rowspan=2, 6− , rowspan=2, , rowspan=2, , - , β⁺ (<0.0012%) , ⁸⁴Kr , -id=Rubidium-85 , 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 releas ...

, style="text-align:right" , 37 , style="text-align:right" , 48 , 84.9117897360(54) , colspan=3 align=center, Stable , 5/2− , 0.7217(2) , , -id=Rubidium-85m , style="text-indent:1em" , ^85mRb , colspan="3" style="text-indent:2em" , 514.0065(22) keV , 1.015(1) μs , IT , ⁸⁵Rb , 9/2+ , , , -id=Rubidium-86 , rowspan=2, ⁸⁶Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 49 , rowspan=2, 85.91116744(21) , rowspan=2, 18.645(8) d , β⁻ (99.99%) , ⁸⁶Sr , rowspan=2, 2− , rowspan=2, , rowspan=2, , - , EC (.0052%) , ⁸⁶Kr , -id=Rubidium-86m , rowspan=2 style="text-indent:1em" , ^86mRb , rowspan=2 colspan="3" style="text-indent:2em" , 556.05(18) keV , rowspan=2, 1.017(3) min , IT (>99.7%) , ⁸⁶Rb , rowspan=2, 6− , rowspan=2, , rowspan=2, , - , β⁻ (<0.3%) , ⁸⁶Sr , - , ⁸⁷Rb Primordial

radionuclide A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess numbers of either neutrons or protons, giving it excess nuclear energy, and making it unstable. This excess energy can be used in one of three ...

Used in

, style="text-align:right" , 37 , style="text-align:right" , 50 , 86.909180529(6) , 4.97(3)×10¹⁰ y , β⁻ , ⁸⁷Sr , 3/2− , 0.2783(2) , , -id=Rubidium-88 , ⁸⁸Rb , style="text-align:right" , 37 , style="text-align:right" , 51 , 87.91131559(17) , 17.78(3) min , β⁻ , ⁸⁸Sr , 2− , , , -id=Rubidium-88m , style="text-indent:1em" , ^88mRb , colspan="3" style="text-indent:2em" , 1373.8(3) keV , 123(13) ns , IT , ⁸⁸Rb , (7+) , , , -id=Rubidium-89 , ⁸⁹Rb , style="text-align:right" , 37 , style="text-align:right" , 52 , 88.9122781(58) , 15.32(10) min , β⁻ , ⁸⁹Sr , 3/2− , , , -id=Rubidium-90 , ⁹⁰Rb , style="text-align:right" , 37 , style="text-align:right" , 53 , 89.9147976(69) , 158(5) s , β⁻ , ⁹⁰Sr , 0− , , , -id=Rubidium-90m , 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 , -id=Rubidium-91 , ⁹¹Rb , style="text-align:right" , 37 , style="text-align:right" , 54 , 90.9165373(84) , 58.2(3) s , β⁻ , ⁹¹Sr , 3/2− , , , -id=Rubidium-92 , rowspan=2, ⁹²Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 55 , rowspan=2, 91.9197285(66) , rowspan=2, 4.48(3) s , β⁻ (99.99%) , ⁹²Sr , rowspan=2, 0− , rowspan=2, , rowspan=2, , - , β⁻, n (0.0107%) , ⁹¹Sr , -id=Rubidium-93 , rowspan=2, ⁹³Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 56 , rowspan=2, 92.9220393(84) , rowspan=2, 5.84(2) s , β⁻ (98.61%) , ⁹³Sr , rowspan=2, 5/2− , rowspan=2, , rowspan=2, , - , β⁻, n (1.39%) , ⁹²Sr , -id=Rubidium-93m , style="text-indent:1em" , ^93mRb , colspan="3" style="text-indent:2em" , 4423.1(15) keV , 111(11) ns , IT , ⁹³Rb , (27/2−) , , , -id=Rubidium-94 , rowspan=2, ⁹⁴Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 57 , rowspan=2, 93.9263948(22) , rowspan=2, 2.702(5) s , β⁻ (89.7%) , ⁹⁴Sr , rowspan=2, 3− , rowspan=2, , rowspan=2, , - , β⁻, n (10.3%) , ⁹³Sr , -id=Rubidium-94m1 , style="text-indent:1em" , ^94m1Rb , colspan="3" style="text-indent:2em" , 104.2(2) keV , 130(15) ns , IT , ⁹⁴Rb , (0−) , , , -id=Rubidium-94m2 , style="text-indent:1em" , ^94m2Rb , colspan="3" style="text-indent:2em" , 2074.9(14) keV , 107(16) ns , IT , ⁹⁴Rb , (10−) , , , -id=Rubidium-95 , rowspan=2, ⁹⁵Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 58 , rowspan=2, 94.929264(22) , rowspan=2, 377.7(8) ms , β⁻ (91.3%) , ⁹⁵Sr , rowspan=2, 5/2− , rowspan=2, , rowspan=2, , - , β⁻, n (8.7%) , ⁹⁴Sr , -id=Rubidium-95m , style="text-indent:1em" , ^95mRb , colspan="3" style="text-indent:2em" , 835.0(6) keV , <500 ns , IT , ⁹⁵Rb , 9/2+# , , , -id=Rubidium-96 , rowspan=2, ⁹⁶Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 59 , rowspan=2, 95.9341334(36) , rowspan=2, 201.5(9) ms , β⁻ (86.3%) , ⁹⁶Sr , rowspan=2, 2− , rowspan=2, , rowspan=2, , - , β⁻, n (13.7%) , ⁹⁵Sr , -id=Rubidium-96m1 , style="text-indent:1em" , ^96m1RbOrder of ground state and isomer is uncertain. , colspan="3" style="text-indent:2em" , 0(200)# keV , 200# ms
1 ms, , , 1(+#) , , , -id=Rubidium-96m2 , style="text-indent:1em" , ^96m2Rb , colspan="3" style="text-indent:2em" , 1134.6(11) keV , 1.80(4) μs , IT , ⁹⁶Rb , (10−) , , , -id=Rubidium-97 , rowspan=2, ⁹⁷Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 60 , rowspan=2, 96.9371771(21) , rowspan=2, 169.1(6) ms , β⁻ (74.5%) , ⁹⁷Sr , rowspan=2, 3/2+ , rowspan=2, , rowspan=2, , - , β⁻, n (25.5%) , ⁹⁶Sr , -id=Rubidium-97m , style="text-indent:1em" , ^97mRb , colspan="3" style="text-indent:2em" , 76.6(2) keV , 5.7(6) μs , IT , ⁹⁷Rb , (1/2,3/2)− , , , -id=Rubidium-98 , rowspan=3, ⁹⁸Rb , rowspan=3 style="text-align:right" , 37 , rowspan=3 style="text-align:right" , 61 , rowspan=3, 97.941632(17) , rowspan=3, 115(6) ms , β⁻(85.65%) , ⁹⁸Sr , rowspan=3, (0−) , rowspan=3, , rowspan=3, , - , β⁻, n (14.3%) , ⁹⁷Sr , - , β⁻, 2n (0.054%) , ⁹⁶Sr , -id=Rubidium-98m1 , style="text-indent:1em" , ^98m1Rb , colspan="3" style="text-indent:2em" , 73(26) keV , 96(3) ms , β⁻ , ⁹⁸Sr , (3+) , , , -id=Rubidium-98m2 , style="text-indent:1em" , ^98m2Rb , colspan="3" style="text-indent:2em" , 178.5(4) keV , 358(7) ns , IT , ⁹⁸Rb , (2−) , , , -id=Rubidium-99 , rowspan=2, ⁹⁹Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 62 , rowspan=2, 98.9451192(43) , rowspan=2, 54(4) ms , β⁻ (82.7%) , ⁹⁹Sr , rowspan=2, (3/2+) , rowspan=2, , rowspan=2, , - , β⁻, n (17.3%) , ⁹⁸Sr , -id=Rubidium-100 , rowspan=3, ¹⁰⁰Rb , rowspan=3 style="text-align:right" , 37 , rowspan=3 style="text-align:right" , 63 , rowspan=3, 99.950332(14) , rowspan=3, 51.3(16) ms , β⁻ (94.3%) , ¹⁰⁰Sr , rowspan=3, 4−# , rowspan=3, , rowspan=3, , - , β⁻, n (5.6%) , ⁹⁹Sr , - , β⁻, 2n (0.15%) , ⁹⁸Sr , -id=Rubidium-101 , rowspan=2, ¹⁰¹Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 64 , rowspan=2, 100.954302(22) , rowspan=2, 31.8(33) ms , β⁻ (72%) , ¹⁰¹Sr , rowspan=2, 3/2+# , rowspan=2, , rowspan=2, , - , β⁻, n (28%) , ¹⁰⁰Sr , -id=Rubidium-102 , rowspan=2, ¹⁰²Rb , rowspan=2 style="text-align:right" , 37 , rowspan=2 style="text-align:right" , 65 , rowspan=2, 101.960008(89) , rowspan=2, 37(4) ms , β⁻, n (65%) , ¹⁰¹Sr , rowspan=2, (4+) , rowspan=2, , rowspan=2, , - , β⁻ (35%) , ¹⁰²Sr , -id=Rubidium-103 , ¹⁰³Rb , style="text-align:right" , 37 , style="text-align:right" , 66 , 102.96440(43)# , 26(11) ms , β⁻ , ¹⁰³Sr , 3/2+# , , , -id=Rubidium-104 , ¹⁰⁴Rb , style="text-align:right" , 37 , style="text-align:right" , 67 , 103.97053(54)# , 35# ms
550 ns, , , , , , -id=Rubidium-105 , ¹⁰⁵Rb , style="text-align:right" , 37 , style="text-align:right" , 68 , , , , , , , , -id=Rubidium-106 , ¹⁰⁶Rb , style="text-align:right" , 37 , style="text-align:right" , 69 , , , , , , ,

Rubidium-87

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 Density, densities is cooled to temperatures very close to absolute zero#Relation with Bose–Einste ...

s in dilute atomic gases. 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 semiconductor laser or diode laser) is a semiconductor device similar to a light-emitting diode in which a diode p ...

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

List of isotopes

Rubidium-87

See also

References