Scandium Group Elements discoveries

We have already briefly mentioned the discovery of scandium in the chapter devoted to REEs (see p. 130). Although many of scandium s properties are similar to those of rare earths, D. I. Mendeleev predicted that the element would be a boron analogue in the third group of the periodic system. His prediction proved to be accurate enough. Scandium was discovered by the Swedish chemist L. Nilson on March 12, 1879, his article On Scandium, a New Rare Metal was published and on March 24 it was discussed at a session of the Paris Academy of Sciences. 

In group 3, we find scandium, Sc, yttrium, Y, and lanthanumm. La, the latter with atomic number 57. One step to the right we expect to find the atomic number 58. But instead there is number 72, Hf. 14 elements are missing This chapter is devoted to the exciting story of discovery and discoverers, and descriptions of the modern uses of these high-tech elements Sc, Y, La and lanthanides. 

This discovery completed the sequence of 14 elements occurring between the atomic numbers 58 and 71 inclusive. The group did not fit into the original periodic tables and was included as the separate lanthanide series . Lanthanum itself, together with two other group 3A elements, yttrium and scandium (and sometimes thorium), is often included with the lanthanide series elements in discussions of the REE. This is because they frequently occur together in rare earth minerals, having similarities in ionic radii and chemical activity. 

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