Yttrium compound

The sacrificial core approach entails depositing a coating on the surface of particles by either the controlled surface precipitation of inorganic molecular precursors from solution or by direct surface reactions [2,3,5,6,8,9,33-35,38], followed by removal of the core by thermal or chemical means. Using this approach, micron-size hollow capsules of yttrium compounds [2], silica spheres [38], and monodisperse hollow silica nanoparticles [3,35] have been generated. 

Cerium-doped yttrium compounds (aiuminates and silicates) cover a very broad spectral range in television tubes. 

Alloys with Yttrium compounds Uranium compounds Plutonium compounds ... 

Toxicology. Yttrium compounds cause pulmonary irritation in animals. 

The crystal chemistry of BajRC C has been systematically studied by single-crystal and powder diffraction methods with R = La, Pr,... Yb, in addition to the conventional yttrium compound [(52)(53) (54) and references therein]. With the exception of La, Pr, and Tb, the substitution of Y with rare-earth metals has little or no effect on the superconductivity, with the values of Tc ranging from 87 to 95K. Also, a relatively small change is observed in the cell constants of these compounds. The La, Pr, and Tb-substituted materials are not superconductors. A detailed structural analysis of the Pr case (52) did not show any evidence of a superstructure or the presence of other differences with the atomic configuration of the yttrium prototype. 

The yttrium compound with LiR gave the crystalline [Y(44) CH(SiMe3)2 ] or the oily CH2SiMe3 analogue From the latter and benzene, or the chloride and LiPh, the product was 67 Reduction of the Y or Lu chloride with KCg in toluene/diethyl ether in the presence of naphthalene, 2-MeC]oH7 or anthracene gave crystalline [ Ln(44) 2-(p-ri" r " -CioH7R)] (R = H orMe) or Ln(44) 2(p-r il -Ci4Hio)], which were fluxional in solution. 

As discussed earlier, yttrium resembles the later lanthanides strongly in its chemistry, so that throughout this book, discussion of lanthanide chemistry includes yttrium, and its compounds will not be examined in this chapter. To give a few, almost random, examples of yttrium compounds strongly resembling those of the later lanthanides ... 

Yttrium compounds are frequently useful host materials for later Ln + ions, as mentioned in Section 5.4.4 Eu Y2O2S is the standard material for the red phosphor in virtually all colour and television cathode ray tubes, whilst Eu Y203 is used for energy-efficient fluorescent tubes. Yttrium oxide is used to stabilize zirconia (YSZ), yttrium iron garnets (YIG) are used in microwave devices, and of course YBa2Cu307 is the classic warm superconductor. Yttrium, like scandium, is naturally monoisotopic. Y has I = 1/2 though signals can be difficult to observe, valuable information can be obtained from NMR studies. 

Question 7.5 Why are yttrium compounds good host materials for heavier Ln + ions Answer 7.5 Because Y + has no f (or d electrons), its compounds have no absorptions in the visible region of the spectrum and do not affect the magnetic properties of any added lanthanide ions. Because its ionic radius is similar to that of Ho +, it can accommodate several of the later lanthanide ions with minimal distortion. 

Several other research groups extended their work to endohedral yttrium compounds. The Rice-Minnesota University (Weaver et al., 1992) and Nagoya University (Shinohara et al., 1992a) research groups also reported solvent-extractable Y Cg2 and Y2 Cg2 fullerenes and observed the ESR hfs of Y Cs2. From the hfs analyses both groups concluded that the charge state of the Y atom is 3+ and that a similar... 

Cp2Ln[ BuNC(Bu)N Bu] (Ln = Er, Y, Gd) (Figure 36c) were prepared by reaction of Cp2LnBu (generated in situ) with A, iV -di-ferf-butylcarbodiimide that proceeds via monoinser-tion of carbodiimide into the Ln-C a-bond. The structurally characterized yttrium compound is a good catalyst for the cyclotrimerization of phenylisocyanate. ... 

Argonne was the first lab to report the growth, crystal structure, and superconducting transition temperature of a single crystal of the yttrium compounds. The first ones were only 0.3 millimeters long, but they packed a wallop. 

It soon became apparent, once the structure of the yttrium compound was bared, that either or both of two central features might account for superconductivity at those record-high temperatures. One was the puckered, two-dimensional plane of copper and oxygen atoms ilar to the flat plane seen earlier in the structure of another superconductor, made of lanthanum, strontium, and copper oxide, that became superconducting at around 40° K. The other was unexpected the one-dimensional chain of copper and oxygen atoms, a sequence unknown in earlier superconductors. The challenge was fairly clear to both theorists and experimentalists. Were the planes or the chains responsible for superconductivity above 90° K ... 

Pipes, valves, fittings, heat exchangers, or magnetic, electrostatic, or other collectors made of graphite or coated in graphite, yttrium, or yttrium compounds resistant to the heat and corrosion of uranium vapour. 

Con arable small jyc coupling constants around 20 Hz are typical for binuclear yttrium compounds with bridging alkyl groups. See for example C. J. Schaverien, Organometallics 1994,13, 69. 

The only yttrium compound of commercial interest is yttrium oxide (Y2O3). Yttrium oxide is used to make phosphors for color television sets and in crystals used in microwave detection instruments. 

A range of silicon oxynitrides is also formed with heavy elements such as yttrium and lanthanum. The yttrium compounds include Y2S1303N4 (N-melilite), Y4Si207N2 (N-YAM or J-phase), Y5Si30 2N and YSiOaN. The Si NMR shifts of these... 

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