Thulium preparation

Moseley s work not only shed much fight on the periodic system and the relationships between known elements and the radioactive isotopes, but was also a great stimulus in the search for the few elements remaining undiscovered (11). One of the first chemists to utilize the new method was Professor Georges Urbain of Paris, who took his rare earth preparations to Oxford for examination. Moseley showed him the characteristic fines of erbium, thulium, ytterbium, and lutetium, and confirmed in a few days the conclusions which Professor Urbain had made after twenty years... 

Even more striking in the old tooth is the abundance of rare earths (dysprosium, holmium, erbium, thulium, ytterbium, and lutetium) and the elements tantalum, tungsten, gold, thorium, and uranium. Rare earth minerals are found in Scandinavia (in fact, many rare earth elements were discovered there), but what were they used for Did people prepare food with them Did they somehow get into the food chain ... 

The first non-classical divalent lanthanide iodide Tml2(DME)3 (DME = dimethoxyethane), which is prepared by the reaction of thulium metal with iodine under argon (Equation 8.33), was reported in 1997 [101]. Subsequently, Dyl2(DME)3 andNdl2(THF)5 have been synthesized by an analogous manner. The success of the synthesis of non-classical divalent lanthanide iodides opens up a new area in divalent lanthanide chemistry [102, 103]. 

The thulium (III) ion exhibits spectrally narrow light emission at about 480 nm. Li and coworkers were the first to use the Tm + ion in OLEDs [65]. They prepared a Tm complex Tm(acac)3(phen) and constructed double-layer cells with structure ITO/PVK/Tm complex/Al. The electroluminescence spectrum of the OLED with drive voltage 10 V and the photoluminescence spectrum with excitation wavelength at 350 nm are shown in Figure 11.29. The emitting intensity of 6.0cdm was achieved when a 16 V forward bias voltage was applied. 

Biborides of holmium and thulium have been prepared from the elements.332 They belong to the same class of structures as A1B2. The structures of HoCo2B2, PrCo2B2, and Y bCo3B2 have also been determined.333... 

Thulium in a fairly pure state may be obtained by the long-continued fractionation of a bromate series. The separation of erbium and thulium is fairly satisfactory by this method alone. According to Welsbach 1 thulium is a mixture of three elements which he designated as thulium I, II, and III. Probably no better thulium material has ever been obtained than that prepared by James2 using the bromate method, which gave a homogeneous product after 15,000 operations. 

Pure EuCg and YbCg can be prepared by intercalation in graphite single crystals, but only superficial reaction has been obtained for samarium and thulium. The use of pyrographite samples also leads to superficial reactions. 

The well-known Sm ry -arene complexes are generally prepared by the reaction of arenes with rare-earth trihalides in the presence of aluminium halides. This reaction was also effective with samarium diiodide and was extended to thulium diiodide however, an attempt to react Tml2 with naphthalene in toluene in the presence of aluminium trichloride was not successful but resulted in the isolation of an ry -toluene complex of Tm [77 -(CH3C6H5)Tm(AlCl4)3] (Figure 6) (Fagin et al., 2005). 

Two ternary thulium palladium silicides have been characterized. TmPd2Si has the ordered Fe3C-type of structure with space group Pnma and lattice parameters a — 7.201(2), b = 6.927(2) and c = 5.452(2) (Moreau et al., 1982 X-ray powder data). For sample preparation, see YPd 2Si. 

G. Urbain, whose name was mentioned in the first lines of this chapter, contributed greatly to the development of REEs chemistry. He perfected the methods of their separation, obtained some oxides in a very pure form (to prepare pure thulium he performed 15 000 recrystallizations), redetermined the atomic masses but could not succeed in discovering a new element himself. 

Ammonia synthesis catalysts of high activity, prepared from alkali metal ferrocyanide with the addition of aluminum and lutetium and/or thulium. Y. U. A. Lyubchenko and L. M. Dmitrenko. SU 417153 (1979). 

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