Hydrogen rare-earth compounds

Binary rare-earth compounds such as carbides, sulfides, nitrides, and hydrides have been used to prepare anhydrous trihalides, but they offer no special advantage. Treating these compounds at a high temperature with a halogen (98) or hydrogen halide (115) produces the trihalide, e.g.,... 

The R2Fei4B (R - rare-earth) compounds absorb a copious amount of hydrogen readily and form stable hydrides at room temperature [2-4]. The changes in the magnetic characteristics of these compounds which occur due to the hydrogen absorption are of great fundamental and technological interest. 

The name comes from the Latin Lutetia Parisorum, meaning the city of Paris. In 1907, Georges Urbain (1872-1938) isolated what he called lutecia from ytterbia, one of the rare-earth compounds that had previously been considered an element. In 1949, IUPAC modified the spelling. Because Auer von Welsbach was also working on these materials, the element is sometimes known as cassiopeium. Lutetium is part of the complex yttria family of rare earths. Lutetium emits beta radiation and has been used as in a limited fashion as a catalyst for hydrogenation and other chemical processes. 

Table 2.1. Structures of Laves-phase Fe2-rare-earth compounds (CIS) exposed to hydrogen gas at a pressure of 5 MPa and various temperatures for 86.4 ks, including the crystallization temperatures Tx of the hydrogen-induced amorphous alloys [2.33]...

Fig. 22. Hydrogen plateau pressures in various series of rare earth compounds.

Laser isotope separation techniques have been demonstrated for many elements, including hydrogen, boron, carbon, nitrogen, oxygen, sHicon, sulfur, chlorine, titanium, selenium, bromine, molybdenum, barium, osmium, mercury, and some of the rare-earth elements. The most significant separation involves uranium, separating uranium-235 [15117-96-1], from uranium-238 [7440-61-1], (see Uranium and uranium compounds). The... 

Buschow, K.H.J. (1984) Hydrogen absorption in intermetallic compounds. In Handbook on the Physics and Chemistry of Rare Earths, eds. Gschneidner Jr., K.A., and Eyring, L. (North-Holland, Amsterdam), Vol. 6, p. 1. 

In an interesting series of experiments Van Mai and co-work-ers (12, 13, 14) have found that if rare earths are combined with transition metals at high temperatures, the alloy will absorb large amounts of hydrogen as hydrides under mild conditions 1 atm. H2 and room temperature. Some examples of these compounds and their hydrides are ... 

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