Radioactive rubidium

The element revealed itself through spectacular violet-colored flames and several red spectral lines. The metal melts at 38 °C, is very soft, and extremely reactive (burns in air and reacts violently with water). Rubidium is stored under mineral oil. It is suitable as a scavenger (oxygen capture) in vacuum tubes, where it is deposited on the glass as a mirror. It can also be found in photocells and phosphors for screens (for example, for air-traffic controllers. Not physiologically important. The radioactive rubidium-87 is useful for age determination in geochronology (half-life ca. 50 billion years). 

The calixspherands form kinetically stable complexes with Na+, K+ and Rb+. The kinetic stability of the different complexes, which can be determined by H NMR spectroscopy or by a new method25 based on the exchange of radioactive rubidium or sodium in the complexes for non-radioactive sodium in different solvents, is strongly increased when the size of the group on the central aromatic ring of the m-terphenyl is increased. Due to the highly shielded cavity, calixspherands 22b,c also form kinetically stable complexes with Ag+.26... 

Strontium isotopes can be used to determine the ages of rocks. Radioactive rubidium 87 decays into strontium 87, with a half-life of 4.9 billion years. Geologists can use the ratio of Sr-87 to naturally occurring... 

Rubidium The stable isotopes Rb and Rb were determined by direct ICP-MS measurements. It should be pointed out that the original intention was to isolate the individual alkali and alkaline earth metals by using cation and ion-exchange columns. The radioactive rubidium and barium isotopes had, however, decayed before dissolution of the samples and therefore only stable isotopes of these elements were determined (by ICP-MS), with the exception of °Sr, Cs, and Cs. 

The alkali metals form a homogeneous group of extremely reactive elements which illustrate well the similarities and trends to be expected from the periodic classification, as discussed in Chapter 2. Their physical and chemical properties are readily interpreted in terms of their simple electronic configuration, ns, and for this reason they have been extensively studied by the full range of experimental and theoretical techniques. Compounds of sodium and potassium have been known from ancient times and both elements are essential for animal life. They are also major items of trade, commerce and chemical industry. Lithium was first recognized as a separate element at the beginning of the nineteenth eentury but did not assume major industrial importance until about 40 y ago. Rubidium and caesium are of considerable academic interest but so far have few industrial applications. Francium, the elusive element 87, has only fleeting existence in nature due to its very short radioactive half-life, and this delayed its discovery until 1939. 

Robertson [ 57 ] has measured the adsorption of zinc, caesium, strontium, antimony, indium, iron, silver, copper, cobalt, rubidium, scandium, and uranium onto glass and polyethylene containers. Radioactive forms of these elements were added to samples of seawater, the samples were adjusted to the original pH of 8.0, and aliquots were poured into polyethylene bottles, Pyrex-glass bottles and polyethylene bottles contained 1 ml concentrated hydrochloric acid to bring the pH to about 1.5. Adsorption on the containers was observed for storage periods of up to 75 d with the use of a Nal(Tl) well crystal. Negligible adsorption on all containers was registered for zinc, caesium, strontium, and... 

They produce distinctive colored flames when burned lithium = crimson sodium = yellow potassium = violet rubidium = purple cesium = blue and the color of francium s flame is not known. Many of francium s characteristics have not been determined owing to the fact that it is rare and all of its many radioactive isotopes have short half-lives. 

ISOTOPES There are 30 isotopes of rubidium, ranging from Rb-75 to Rb-98. Rb-85 is the only stable form of rubidium and constitutes 72.17% of all rubidium isotopes found in the Earth s crust. Rb-87 is radioactive (a half-life of 4.9x10 ° years) and makes up about 27.83% of the remainder of rubidium found in the Earth s crust. All the other 28 isotopes make up a tiny fraction of all the rubidium found on Earth and are radioactive with very short half-lives. 

Rubidium metal and its salts bave very few commercial apphcations. They are used in research involving magnetohydrodynamics and thermoionic experiments. Rubidium is used in pbotocells. The metal also is a getter of oxygen in vacuum tubes. The beta-emitter rubidium -87 is used to determine age of some rocks and minerals. Radioisotopes of rubidium have been used as radioactive tracers to trace the flow of blood in the body. The iodide salt treats goiters. Rubidium salts are in pharmaceuticals as soporifics, sedatives, and for treating epilepsy. 

Rubidium-82 myocardial perfusion images are used to study patients with myocardial ischemia or infarction. An example of this study is shown in Figure 8. Three patients with known myocardial infarction were imaged with Rb-82. Twenty millicuries of Rb-82 were administered in a 20 ml bolus in 20 sec. Data accumulated from 0-90 seconds post infusion show the blood pool as the radioactivity enters the right side of the heart, flows out to the lungs, and returns to the left side of the heart. Data accumulated from 90-300 seconds reflect uptake of Rb-82 in the myocardium as distributed by blood flow. These results by a non-invasive procedure correlated with the results of catheterized contrast x-ray studies (27,28). 

In the rubidium-strontium age dating method, radioactive 87Rb isotope with a natural isotope abundance of 27.85 % and a half-life of 4.8 x 1010 a is fundamental to the 3 decay to the isobar 87 Sr. The equation for the Rb-Sr method can be derived from Equation (8.9) ... 

Whereas the abundance of 87 Sr in rubidium rich rocks changes over time due to the radioactive 3... 

This paper presents the more important data and conclusions from three reports which describe the uptake behavior of the vaporized oxides of molybdenum, tellurium, and rubidium by molten and solid substrates at high temperatures (I, 2, 3). These oxides were used as the vapor species because of their relatively high volatility and because of their importance as radioactive constituents, or the precursors of important constituents, of radioactive fallout particles. 

Radioactive dating -use of radioisotopes [RADIOISOTOPES] (Vol 20) -use of rubidium compounds [RUBIDIUM AND RUBIDIUM COMPOUNDS] (Vol 21)... 

Radioactive tracer -bismuth as [BISMUTH COMPOUNDS] (Vol 4) -rubidium as [RUBIDIUMAND RUBIDIUM COMPOUNDS] (Vol21)... 

K is a (3 -emitting nuclide that is the predominant radioactive component of normal foods and human tissue. Due to the 1460-keV 7 ray that accompanies the (3 decay, it is also an important source of background radiation detected by 7-ray spectrometers. The natural concentration in the body contributes about 17 mrem/y to the whole body dose. The specific activity of 40K is approximately 855 pCi/g potassium. Despite the high specific activity of 87Rb of 2400 pCi/g, the low abundance of rubidium in nature makes its contribution to the overall radioactivity of the environment small. 

Group I consists of the five metals lithium, sodium, potassium, rubidium and caesium, and the radioactive element francium. Lithium, sodium and potassium are commonly available for use in school. They are all very reactive metals and they are stored under oil to... 

When small amounts of isotopes are thus synthesized and must be separated from other chemical elements in a mixture, chemical periodicity helps for example, radioactive francium (group 1) can be extracted from its mixture with radium (group 2) or polonium (group 16) by adding cesium or rubidium (group 1). 

Several rubidium salts exhibit radioactivity,14 among them the sulphate,15 chloride, and chlorate.16 The action of the sulphate on the photographic plate is more powerful than that of potassium sulphate.17... 

---