Rubidium, a soft, silvery-white alkali metal, stands as one of the most fascinating elements in the periodic table. Its journey from discovery in 1861 to its modern applications encompasses remarkable scientific achievements, from the invention of spectroscopy to the creation of Bose-Einstein condensates. This reactive metal, whose name derives from the deep red lines in its emission spectrum, has played pivotal roles in advancing atomic physics, medical imaging, and our understanding of the universe’s age. Though rarely encountered in everyday life, rubidium’s unique properties have made it indispensable in cutting-edge technology and fundamental research, positioning it as a quiet but essential contributor to scientific progress.

Be sure to check out all other critical raw materials (CRMs), as well. 

A History Of Rubidium

The story of rubidium unfolds as a testament to scientific ingenuity and technological advancement. From its spectroscopic discovery in German mineral springs to its role in creating exotic states of matter and enabling precise medical diagnostics, rubidium has consistently pushed the boundaries of what is possible in physics and chemistry. This chronology traces the element’s journey through more than 160 years of scientific discovery and application.

Chronology

• 1861 – Robert Bunsen and Gustav Kirchhoff discovered rubidium in the mineral lepidolite through flame spectroscopy at the University of Heidelberg, identifying it by two distinctive deep red spectral lines; processed 150 kilograms of lepidolite ore to extract enough rubidium for study, obtaining only about 1.5% of the mineral as rubidium; named the element rubidium from the Latin word “rubidus” meaning “deepest red” after the color of its emission spectrum lines; began large-scale isolation of rubidium compounds, processing 44,000 liters of mineral water to obtain 9.2 grams of rubidium chloride; using rubidium chloride, estimated the atomic weight of rubidium to be 85.36, remarkably close to the modern accepted value of 85.47; Bunsen attempted to produce metallic rubidium by electrolysis of molten rubidium chloride but obtained a blue substance that showed no metallic properties under microscopic examination; in a second attempt, Bunsen successfully reduced rubidium by heating charred rubidium tartrate, producing pyrophoric metallic rubidium; Bunsen determined the density and melting point of rubidium metal, with values differing by less than 0.1 g/cm³ and 1°C from modern accepted values [1]
• 1908 – The slight radioactivity of rubidium was discovered [2]
• 1920 – Rubidium found its first significant industrial applications in research and development, particularly in chemical and electronic applications [3]
• 1928 – A sample of pure rubidium metal was produced, representing a significant advance in isolation techniques [4]
• 1940 – Rubidium-87 was recognized as an unstable isotope, though its use in dating would not begin until the advent of modern mass spectrometry [5]
• 1948 – The decay of rubidium-87 to stable strontium-87 through beta decay was confirmed after years of scientific discussion [2]
• 1950 – The development of modern mass spectrometry enabled the use of rubidium-87 for radiometric dating [5]
• 1954 – Love et al. demonstrated that rubidium’s biological behavior was comparable to potassium and that its myocardial muscle uptake was proportional to coronary artery blood flow [6]
• 1955 – A byproduct of potassium production called Alkarb became a main source for rubidium, containing 21% rubidium [1]
• 1958 – Peter Bender and colleagues published work on rubidium atomic clocks in Physical Review Letters [7]
• 1961 – The rubidium-strontium dating method became the first widely used dating system utilizing the isochron method [8]
• 1967 – The U.S. Navy began sending experimental atomic clocks, including rubidium-based ones, into space [9]
• 1969 – The International Union of Pure and Applied Chemistry recommended the current atomic weight value of rubidium as 85.4678(3) based on new isotope-abundance measurements [10]
• 1977 – The GPS satellite network was launched with each satellite carrying both cesium and rubidium-based atomic clocks [9]
• 1982 – First human injections of rubidium-82 for medical imaging took place, demonstrating diagnostic accuracy higher than technetium-99m SPECT [6]
• 1989 – The rubidium-82 generator (CardioGen-82) was approved by the FDA and delivered in the USA by Bracco Diagnostics for clinical use in cardiac imaging [6]
• 1995 – Eric Cornell and Carl Wieman created the first Bose-Einstein condensate using approximately 2,000 rubidium-87 atoms cooled to 170 nanokelvin at JILA, University of Colorado Boulder on June 5 at 10:54 AM, lasting for 15-20 seconds; Wolfgang Ketterle at MIT produced a Bose-Einstein condensate using sodium atoms later that same year [11]
• 1997 – Researchers under Wolfgang Ketterle at MIT developed an atom laser based on the Bose-Einstein condensate discovery using rubidium [11]
• 1999 – NIST scientists created a device that shoots out streams of rubidium atoms based on Bose-Einstein condensate technology [12]
• 2000 – The Voyager spacecraft RTGs, after 23 years of operation, showed rubidium components operating at about 67% of original capacity [13]
• 2001 – Eric Cornell, Carl Wieman, and Wolfgang Ketterle shared the Nobel Prize in Physics for achieving Bose-Einstein condensation in dilute gases of alkali atoms; Cornell and Wieman’s team demonstrated a “Bosenova” – a microscopic explosion of a Bose-Einstein condensate similar to a supernova [11]
• 2011 – High-performance laser-pumped rubidium frequency standard for satellite navigation was developed, improving rubidium atomic clock technology [14]
• 2012 – Rubidium atoms were used in research on the FE-5680A atomic clock units, with widespread adoption for precision timing applications [15]
• 2013 – The NIST-F2 cesium clock was developed, providing comparison standards for rubidium atomic clocks with hyperfine frequency measurements showing rubidium at ~6.8 GHz versus cesium at ~9.19 GHz [16]
• 2014 – Zamora et al. published research on rubidium abundances in massive Galactic asymptotic giant branch stars, revealing extreme rubidium enrichment patterns [17]
• 2015 – Meta-analyses showed rubidium-82 PET myocardial perfusion imaging had higher diagnostic accuracy than SPECT imaging [6]
• 2016 – Compact chip-scale rubidium atomic clocks gained wider adoption for telecommunications and GPS applications [18]
• 2017 – Advanced pseudo-dynamical models were developed to explain extreme rubidium abundances observed in asymptotic giant branch stars [17]
• 2018 – An experiment aboard the International Space Station cooled rubidium atoms to ten-millionth of a degree above absolute zero, creating a Bose-Einstein condensate in space [19]
• 2019 – FDA required safety labeling changes including boxed warnings for rubidium-82 generators due to incidents of excess radiation exposure from user error [20]
• 2020 – Scientists repeated the demonstration of a Bose-Einstein condensate with rubidium on the International Space Station, holding the record for the coldest object in space [19]
• 2021 – Galileo satellites began using passive hydrogen maser and rubidium atomic clocks for improved navigation timing; scientists at JILA demonstrated gravitational redshift measurements using strontium clocks with precision of 7.6×10⁻²¹ [16]
• 2022 – Major pharmaceutical company received approval for novel rubidium-based medical imaging agent offering improved diagnostic capabilities for cardiovascular diseases [21]
• 2023 – Rubidium atomic clocks were launched for use in 5G networks, enhancing network accuracy and stability; commercial chip-scale rubidium atomic clock adoption rose approximately 28% [18]
• 2024 – Chinese scientists at the Chinese Academy of Sciences developed new rubidium atomic clock using xenon starter gas achieving 100s frequency stability of 9 × 10⁻¹⁵; adaptive Kalman filtering algorithm for rubidium atomic clock discipline achieved clock error standard deviation better than 2.568 nanoseconds [14]
• 2025 – China successfully extracted rubidium from brine for the first time, marking a potential new source for the element [22]

Final Thoughts

Rubidium’s remarkable journey from a curiosity identified by colored flames to an essential component of atomic clocks, medical diagnostics, and quantum physics exemplifies how fundamental scientific discoveries can lead to transformative applications. While it remains one of the lesser-known elements to the general public, rubidium’s contributions to GPS technology touch billions of lives daily, its role in cardiac imaging saves lives through early disease detection, and its use in creating Bose-Einstein condensates continues to unlock mysteries of quantum mechanics.

As we look to the future, rubidium’s unique properties promise continued relevance in emerging technologies, from quantum computing to advanced medical imaging, ensuring that this “deepest red” element will continue to illuminate new paths in science and technology.

Thanks for reading!

References

[1] Rubidium – Wikipedia – https://en.wikipedia.org/wiki/Rubidium

[2] Isotopes of rubidium – Wikipedia – https://en.wikipedia.org/wiki/Isotopes_of_rubidium

[3] Rubidium | History, Uses, Facts, Physical & Chemical Characteristics – https://periodic-table.com/rubidium/

[4] Rubidium – Element information, properties and uses | Periodic Table – https://periodic-table.rsc.org/element/37/rubidium

[5] Rubidium-strontium dating | EBSCO Research Starters – https://www.ebsco.com/research-starters/science/rubidium-strontium-dating

[6] Story of Rubidium-82 and Advantages for Myocardial Perfusion PET Imaging – PMC – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4566054/

[7] The rubidium atomic clock and basic research | Physics Today | AIP Publishing – https://pubs.aip.org/physicstoday/article/60/11/33/976100/The-rubidium-atomic-clock-and-basic-researchThe

[8] Dating – Rubidium-Strontium, Geochronology, Method | Britannica – https://www.britannica.com/science/dating-geochronology/Rubidium-strontium-method

[9] A Brief History of Atomic Time | NIST – https://www.nist.gov/atomic-clocks/brief-history-atomic-time

[10] Atomic Weight of Rubidium | Commission on Isotopic Abundances and Atomic Weights – https://www.ciaaw.org/rubidium.htm

[11] Bose–Einstein condensate – Wikipedia – https://en.wikipedia.org/wiki/Bose%E2%80%93Einstein_condensate

[12] Bose-Einstein Condensate: A New Form of Matter | NIST – https://www.nist.gov/news-events/news/2001/10/bose-einstein-condensate-new-form-matter

[13] Radioisotope thermoelectric generator – Wikipedia – https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator

[14] Disciplining a Rubidium Atomic Clock Based on Adaptive Kalman Filter – PMC – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11280732/

[15] » Rubidium Clock – part 2 » JeeLabs – https://jeelabs.org/2012/03/11/rubidium-clock-part-2/index.html

[16] Atomic clock – Wikipedia – https://en.wikipedia.org/wiki/Atomic_clock

[17] Rubidium and zirconium abundances in massive Galactic asymptotic giant branch stars revisited | Astronomy & Astrophysics (A&A) – https://www.aanda.org/articles/aa/full_html/2017/10/aa31245-17/aa31245-17.html

[18] Rubidium Atomic Clock Market Size, Share & Outlook to 2033 – https://www.globalgrowthinsights.com/market-reports/rubidium-atomic-clock-market-111688

[19] States of Matter: Bose-Einstein Condensate | Live Science – https://www.livescience.com/54667-bose-einstein-condensate.html

[20] FDA reminds imaging facilities to follow safety procedures for rubidium 82 generators used in Positron Emission Tomography (PET) myocardial perfusion imaging | FDA – https://www.fda.gov/drugs/drug-safety-and-availability/fda-reminds-imaging-facilities-follow-safety-procedures-rubidium-82-generators-used-positron

[21] Rubidium Market Size, Share & Analysis Report 2034 – https://www.marketresearchfuture.com/reports/rubidium-market-27298

[22] Rubidium | Properties, Uses, & Isotopes | Britannica – https://www.britannica.com/science/rubidium