Thulium compounds

In the case of thulium compounds TmSe and TmTe and YI3AI3, distinct multiplet structures due to divalent and trivalent thulium are seen in the 4f region [38]. The multiplet structure in TmTe is more distinct than in the case of TmSe in agreement with magnetic susceptibility data, (i.e.) magnetic moment of TmTe is smaller than that of TmSe. 

Thulium compounds occur mixed with other rare earth compounds in minerals such as monazite, euxenite, and gadolinite. Monazite is about 0.007 percent thulium. 

Some preliminary data have been given for other thulium compounds [165]. C-type TmzOa, Tm(benzoate)3, Tm(oxinate)3, and Tm(acac)3.3H20 all show two thuUum sites, only one of which is quadrupole split. Chemical isomer shifts of 12 and 37 mm s relative to the oxide were found only in TmF3 and TmC respectively, but insufficient information is available for systematic interpretation. 

SCHEME 1 First solution synthesis of a divalent thulium compound [Tml2(DME)3]. 

Some nut trees accumulate mineral elements. Hickory nut is notable as an accumulator of aluminum compounds (30) the ash of its leaves contains up to 37.5% of AI2O2, compared with only 0.032% of aluminum oxide in the ash of the Fnglish walnut s autumn leaves. As an accumulator of rare-earth elements, hickory greatly exceeds all other plants their leaves show up to 2296 ppm of rare earths (scandium, yttrium, lanthanum, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium). The amounts of rare-earth elements found in parts of the hickory nut are kernels, at 5 ppm shells, at 7 ppm and shucks, at 17 ppm. The kernel of the Bra2d nut contains large amounts of barium in an insoluble form when the nut is eaten, barium dissolves in the hydrochloric acid of the stomach. 

The brittle, silvery, shiny metal was long considered the last stable element of the Periodic Table. In 2003 it was unmasked as an extremely weak alpha emitter (half-life 20 billion years). Like thulium, there is only one isotope. Bismuth alloys have low melting points (fuses, fire sprinklers). As an additive in tiny amounts, it imparts special properties on a range of metals. Applied in electronics and optoelectronics. The oxichloride (BiOCl) gives rise to pearlescent pigments (cosmetics). As bismuth is practically nontoxic, its compounds have medical applications. The basic oxide neutralizes stomach acids. A multitalented element. Crystallizes with an impressive layering effect (see right). 

Important scientific and industrial applications for thulium and its compounds remain to be developed. In particular, the photoelectric, semiconductor, and thermoelectric properties of the element and compounds, particularly behavior in the near-infrared region of the spectrum, are being studied. Thulium has been used in phosphors, ferrite bubble devices, and catalysis. Irradiated thulium (169Tm) is used in a portable x-ray unit. 

The compounds 52-54 can be isolated in the form of intensely colored, highly air- and moisture-sensitive crystals. X-ray crystal structure analyses have been carried out on the derivatives 52n and 53p. Figure 16 shows the molecular structure of the thulium derivative 52n [71]. 

The only complexes of lanthanum or cerium to be described are [La(terpy)3][C104]3 175) and Ce(terpy)Cl3 H20 411). The lanthanum compound is a 1 3 electrolyte in MeCN or MeN02, and is almost certainly a nine-coordinate mononuclear species the structure of the cerium compound is not known with any certainty. A number of workers have reported hydrated 1 1 complexes of terpy with praseodymium chloride 376,411,438), and the complex PrCl3(terpy)-8H20 has been structurally characterized 376). The metal is in nine-coordinate monocapped square-antiprismatic [Pr(terpy)Cl(H20)5] cations (Fig. 24). Complexes with a 1 1 stoichiometry have also been described for neodymium 33, 409, 411, 413, 417), samarium 33, 411, 412), europium 33, 316, 411, 414, 417), gadolinium 33, 411), terbium 316, 410, 414), dysprosium 33, 410, 412), holmium 33, 410), erbium 33, 410, 417), thulium 410, 412), and ytterbium 410). The 1 2 stoichiometry has only been observed with the later lanthanides, europium 33, 411, 414), gadolinium, dysprosium, and erbium 33). 

In the thulium + chlorine system a number of such homologues is believed to exist in the region TmQ2+a. Thermal analysis suggests the existence of at least nine compounds in the range 0.04q = f5 < O.II2, i.e. Tm Q2n+i with 25.0 > 8.9. In this case... 

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