Scandium history

Reiterating, the phosphatic mineral of such phosphorites is essentially francolite, a carbonate fluorapatite of somewhat variable composition (McConnell, 1971 Rooney and Kerr, 1967). Although not proven to be contained within the apatitic phase through isomorphic substitution, some of the continental phosphorites are of considerable interest because of accumulations of uranium, thorium, yttrium, rare earths, scandium, and vanadium therein. These rarer components are thought to be related to diagenetic processes, in which case they were extracted from sea water during the early formative histories of the phosphorites. 

Non Rare Earth SATs. Several candidates that meet these criteria have been found, and some of their applications are discussed by Kruger (5). Krugers discussion also contains an excellent accoimt of the early history of this field. In a series of experiments at the Pennsylvania State University, Jester and coworkers (6,7) have used Br" and I" to mimic the movement of soluble species in natural waters. In-EDTA complexes have been used by Behrens et al. (8) to monitor groundwater movement, while Dahl (9) has shown that In(N03)2 could be used to trace water stream patterns and pollutant dispersal in and around the harbor of a Norwegian town. Indium and scandium were used as stable activable tracers for monitoring in-plant movements of water in waste water treatment plants by Craft and Eicholz (10). The entire subject of industrial uses of activable tracers has been reviewed recently by Van Dalen and Wijkstra (II). 

Lanthanum (Z = 57) and the following fourteen lanthanides from cerium (Z = 58) to lutetium (Z = 71) are usually classihed as rare-earth elements. Two more elements can be added to the list yttrium (Z — 39) and scandium (Z = 21) their properties are similar to those of lanthanum and they are linked historically with the rare earths. It was precisely the discovery of yttrium that began the history of rare-earth elements. Scandium, mentioned only briefly here, is considered in greater detail in Chapter 9. 

The history of gallium, scandium, and germanium shows that their discoveries were practically unaffected by the periodic law and periodic system. However, the properties predicted by D. I. Mendeleev for eka-aluminium, eka-boron. 

History is also being read by scientists studying ice cores from glaciers in Iceland. Now Swiss scientists have found that ancient peat bogs can furnish a reliable historical record. Geochemist Wilham Shotyk of the University of Bern has found a 15,000-year window on history by analyzing the lead content of core samples from a Swiss mountainside peat bog [Science 281 (1998) 1635]. Various parts of the core samples were dated by dating techniques (see Chapter 18, Section 18.4, for more information) and analyzed for their scandium and lead contents. 

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