Thulium uses

Many elements such as tin, copper, zinc, lead, mercury, silver, platinum, antimony, arsenic, and gold, which are so essential to our needs and civilization, are among some of the rarest elements in the earth s crust. These are made available to us only by the processes of concentration in ore bodies. Some of the so-called rare-earth elements have been found to be much more plentiful than originally thought and are about as abundant as uranium, mercury, lead, or bismuth. The least abundant rare-earth or lanthanide element, thulium, is now believed to be more plentiful on earth than silver, cadmium, gold, or iodine, for example. Rubidium, the 16th most abundant element, is more plentiful than chlorine while its compounds are little known in chemistry and commerce. 

Thus La and Ce are the most abundant rare earths while Lu and Tm are the most scarce. This leads us finally to the issue of the inappropriate nature of the term rare earth to describe these elements. In fact, the most abundant rare earth, Ce, has about the same abundance in the earth s crust as Cu (copper) and is more abundant than B (boron— a major constituent of all glass), Co (cobalt—a commonly used alloying agent in steelmaking). Ge (germanium— used to make the first transistor), Pb (lead—automobile batteries and gasoline), Sn (tin—as in cans), or U (uranium). Even Tm (thulium), the rarest of the rare earths, is more abundant than Cd (cadmium—a battery component), I (iodine—from the medicine chest), Hg (mercury—as in barometers and thermometers), and certainly Ag (silver), Au (gold), and Pt (platinum). 

The analysis of theoretical calculations performed for lanthanum trichloride shows that, in spite of the use of different calculation procedures, all authors except Adamo and Maldivi (1997,1998) and Vetere et al. (2000) report Vi frequencies lying below V3. This prompted us to carefully analyze the work by Loktyushina et al. (1984) and the FUR spectra of neodymium, dysprosium, and thulium trichlorides reported by Feltrin and Nimziante-Cesaro (1996). 

Such a close agreement between the calculated and experimental enthalpies of formation for samarium, europium, thulium, and ytterbium dichlorides allows us to claim that the calculation scheme used in the framework of this study leads to reliable results provided that the reference values are chosen adequately. 

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