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Copyright (c) 2006-2014 MindTouch Inc.
This file and accompanying files are licensed under the MindTouch Master Subscription Agreement (MSA).
At any time, you shall not, directly or indirectly: (i) sublicense, resell, rent, lease, distribute, market, commercialize or otherwise transfer rights or usage to: (a) the Software, (b) any modified version or derivative work of the Software created by you or for you, or (c) MindTouch Open Source (which includes all non-supported versions of MindTouch-developed software), for any purpose including timesharing or service bureau purposes; (ii) remove or alter any copyright, trademark or proprietary notice in the Software; (iii) transfer, use or export the Software in violation of any applicable laws or regulations of any government or governmental agency; (iv) use or run on any of your hardware, or have deployed for use, any production version of MindTouch Open Source; (v) use any of the Support Services, Error corrections, Updates or Upgrades, for the MindTouch Open Source software or for any Server for which Support Services are not then purchased as provided hereunder; or (vi) reverse engineer, decompile or modify any encrypted or encoded portion of the Software.
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Scandium was one of the elements predicted by Mendeleev in 1871 when he proposed his system for organizing the elements: the periodic table. At the time he called it ekaboron ("like boron") and suggested some of the physical and chemical properties it would have. The existence of scandium was confirmed only 8 years later by Lars Nilson. It is named for the Latin word for Scandinavia.
The metal is lightweight and fairly corrosion-resistant. It also has a high melting point and therefore finds applications in the aerospace industry. Scandium is widely distributed on the earth and has an abundance similar to cobalt and lithium. Most commercial scandium is obtained from the uranium refining process.
The current claim-to-fame for yttrium (named from a Swedish village, Ytterby) is its use in the so-called 1-2-3 oxide superconductors (along with barium and copper). These were the first superconducting materials to function at liquid nitrogen temperatures. The element was discovered in 1789 by Gadolin and finally isolated in 1828 by Wöhler. More than 15 tons of the oxide are now produced each year. In addition to its use in the research of superconductivity, it is also used in phosphors (red) for color television tubes.
Yttrium metal is ductile and silvery. Powdered samples and turnings from machining can burst into flame. Most commercial yttrium is produced from monazite sands which are also the source for most of the rare earth elements.
Discovered in 1893 by Mosander, lanthanum is named from the Greek lanthanein, "to lie hidden". That is an apt description since lanthanum generally occurs along with other so-called rare earth elements and is very difficult to separate. The abundance of the metal is similar to that of zinc or nickel.
Lanthanum is used in the electrodes for high-intensity carbon-arc lamps and also in the production of high-purity europium metal (element 63). The pure metal is silvery white and malleable. It is soft enough to cut with a knife and will oxidize readily in the air as well as react with moisture. For that reason the metal is usually stored under oil or kerosene. Most lanthanum is extracted from monazite sands.
Actinium, named from the Greek aktinos (ray) is a rare, extremely radioactive metal that glows in the dark (the photo shown above is of \(Ac_2O_3\)). It was discovered by Debierne in 1899 and again in 1902 by Giesel. Eventual priority was given to Debierne's work.
Samples of actinium quickly decay to thorium and francium. The longest-lived isotope (Ac-227) has a half-life of 21.8 years. The element is obtained as an impurity in pitchblende, an ore mined for its uranium content. One-tenth of one gram of actinium can be recovered from 1 ton of pitchblende!
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