Alloy datings ru
However, rubidium ions have the same charge as potassium ions, and are actively taken up and treated by animal cells in similar ways.It is the second most electropositive of the non-radioactive alkali metals and melts at a temperature of 39.3 °C (102.7 °F).If the initial amount of Sr is known or can be extrapolated, then the age can be determined by measurement of the Rb and Sr concentrations and of the Rubidium-82, one of the element's non-natural isotopes, is produced by electron-capture decay of strontium-82 with a half-life of 25.36 days.With a half-life of 76 seconds, rubidium-82 decays by positron emission to stable krypton-82.Elemental rubidium is highly reactive, with properties similar to those of other alkali metals, including rapid oxidation in air.On Earth, natural rubidium comprises two isotopes: 72% is the stable isotope, Rb, with a half-life of 49 billion years—more than three times longer than the estimated age of the universe.For several years in the 1950s and 1960s, a by-product of potassium production called Alkarb was a main source for rubidium.Alkarb contained 21% rubidium, with the rest being potassium and a small amount of caesium.
During fractional crystallization, Sr tends to concentrate in plagioclase, leaving Rb in the liquid phase.
Rubidium was discovered in 1861 by Robert Bunsen and Gustav Kirchhoff, in Heidelberg, Germany, in the mineral lepidolite through spectroscopy.
Because of the bright red lines in its emission spectrum, they chose a name derived from the Latin word rubidus, meaning "deep red". Both potassium and rubidium form insoluble salts with chloroplatinic acid, but those salts show a slight difference in solubility in hot water.
Therefore, the less-soluble rubidium hexachloroplatinate (Rb Bunsen and Kirchhoff began their first large-scale isolation of caesium and rubidium compounds with 44,000 litres (12,000 US gal) of mineral water, which yielded 7.3 grams of caesium chloride and 9.2 grams of rubidium chloride.
They tried to generate elemental rubidium by electrolysis of molten rubidium chloride, but instead of a metal, they obtained a blue homogeneous substance which "neither under the naked eye nor under the microscope showed the slightest trace of metallic substance." They presumed it was a subchloride ( In a second attempt to produce metallic rubidium, Bunsen was able to reduce rubidium by heating charred rubidium tartrate.During magma crystallization, rubidium is concentrated together with its heavier analogue caesium in the liquid phase and crystallizes last.