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RUBIDIUM. The Columbia Encyclopedia: Sixth Edition. 2000 (Site not responding. Last check: 2007-11-07) |
 | | 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 earths 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 chemicals. |
 | | Rubidium was discovered with cesium in 1861 by R. Bunsen and G. Kirchhoff; these were the first elements discovered by spectroscopic analysis. |
| www.bartleby.com /aol/65/ru/rubidium.html (231 words) |
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