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rubidium |
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rubidium (r bĭd`ēəm), metallic chemical element; symbol Rb; at. no. 37; at. wt. 85.4678; m.p. 38.89°C;; b.p. 686°C;; sp. gr. 1.53 at 20°C;; valence +1. Rubidium is a very soft silver-white metal. One of the alkali metals alkali metals, metals found in Group 1 of the periodic table . Compared to other metals they are soft and have low melting points and densities. Alkali metals are powerful reducing agents and form univalent compounds...... Click the link for more information. , it is directly below potassium in Group 1 of the periodic table periodic table, chart of the elements arranged according to the periodic law discovered by Dmitri I. Mendeleev and revised by Henry G. J. Moseley . In the periodic table the elements are arranged in columns and rows according to increasing atomic number (see the ..... Click the link for more information. . It is extremely reactive, combining violently with water to form the hydroxide. It oxidizes rapidly, and may ignite when exposed to air. It forms numerous compounds, e.g., halides, oxides, sulfates, and sulfides. Its salts color a flame red. Rubidium is not found uncombined in nature but occurs widely distributed in lepidolite (the major source), carnallite, pollucite, and some rare minerals, and with lithium in seawater, brines, and natural spring waters. Although rubidium is much more abundant in the earth's crust than chromium, copper, lithium, nickel, or zinc, and about twice as abundant in seawater as lithium, it did not become available commercially until the early 1960s as a byproduct of the manufacture of lithium lithium (lĭth`ēəm) [Gr.,=stone], metallic chemical element; symbol Li; at. no. 3; at. wt. 6.941; m.p. about 180.54°C;; b.p. ..... Click the link for more information. chemicals. The metal is obtained by electrolysis or chemical reduction of the fused chloride. It must be kept out of contact with air and water. Rubidium and its salts have few commercial uses. The metal is used in the manufacture of photocells and in the removal of residual gases from vacuum tubes. Rubidium salts are used in glasses and ceramics. Rubidium-87, a radioactive isotope (half-life about 5 × 1011 years), makes up about 28% of natural rubidium; the balance is the stable isotope rubidium-85. Fifteen other isotopes are known. Rubidium was discovered with cesium in 1861 by R. W. Bunsen Bunsen, Robert Wilhelm (bŭn`sən, Ger. rō`bĕrt vĭl`hĕlm b ..... Click the link for more information. and G. R. Kirchhoff Kirchhoff, Gustav Robert (g ..... Click the link for more information. ; these were the first elements discovered by spectroscopic analysis. rubidium a soft highly reactive radioactive element of the alkali metal group; the 16th most abundant element in the earth's crust (310 parts per million), occurring principally in pollucite, carnallite, and lepidolite. It is used in electronic valves, photocells, and special glass. Symbol: Rb; atomic no.: 37; atomic wt.: 85.4678; half-life of 87Rb: 5 × 1011 years; valency: 1, 2, 3, or 4; relative density: 1.532 (solid), 1.475 (liquid); melting pt.: 39.48?C; boiling pt.: 688?C rubidium [rü′bid·ē·əm] (chemistry) A chemical element, symbol Rb, atomic number 37, atomic weight 85.4678; a reactive alkali metal; salts of the metal may be used in glass and ceramic manufacture. How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content. |
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A cardiac PET rest/stress study by rubidium 82 provides not only myocardial perfusion results, but also myocardial viability in less than 45 minutes. A cardiac PET rest/stress study by rubidium 82 provides not only myocardial perfusion results, but also myocardial viability in less than 45 minutes. Our association with Positron and Bracco, developers of a portable Rubidium 82 (Cardiogen) system, will allow us to provide improved patient care and the management of coronary artery disease. |
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