Yttrium trichloride

Solvates of the monohydroxylic alcohols have been extensively studied. The expected pattern of more solvent molecules per chloride molecule is reported for the lanthanide and yttrium trichlorides. For scandium trichloride, the existence of ScCl3-2EtOH and ScCl3-2C6H13OH compares unexpectedly with the tris-alcoholates reported for the n-C6... 

The results in the three preceding subsections conform fairly well to a consistent pattern. However, there are gaps and inconsistencies that require further thermochemical, and in some cases chemical, study. The series of solution enthalpies for the lanthanide trichlorides is satisfactory, but disagreements over the value for the enthalpy of solution of yttrium trichloride in water need resolving, and a modern value for scandium trichloride (at 25°C) would be welcome. The complete absence of enthalpies of solution of tribromides of the lanthanide elements and yttrium is regrettable, as is the lack of a value for scandium triiodide. 

The most studied solvent here is pyridine (Table XXIX (178, 298). The reported solubilities parallel the affinities suggested by known solvates—e.g., YCl3-3py, SmCl3-3py, but PrCl3-2py (cf. Section III,C,2). Qualitative information on related solvents is that neodymium trichloride is very sparingly soluble in aniline, but insoluble in toluidine, pyrrole, piperidine, and quinoline. Praseodymium trichloride is also insoluble in quinoline, but yttrium trichloride is slightly soluble in this solvent (178). 

Solubilities of LaCl3-7H20 and of NdCl3-6H20 in acetone/water mixtures have been reported, and compared with those for chlorides of barium and of the alkali metals (323). For these trichlorides, the solubility increases as acetone is added to water up to about 15% acetone, then decreases (LaCl3 and NdCl3 are effectively insoluble in acetone itself). There is also some information, presented only in graphical form, on solubilities of praseodymium trichloride in water-rich methanol, ethanol, and ether mixtures (314), and one fact on yttrium trichloride in a water/ether mixture (264). 

An interesting selectivity in the transfer of alkyl groups (n-Alk>Me) is observed in these addition reactions. The regioselectivity of the reaction of crotylmagnesium chloride (213) with benzaldehyde strongly depends on the presence of various rare-earth metal chlorides. The a- to y ratio of products can be switched to the opposite by using only another metal salt. Yttrium trichloride gives exclusively y-product, while neodymium trichloride leads to 89% of the a-attack (with 92% of ( )-isomer) (equation 142) °. 

A recent development in this field involves the combination of benzamidi-nate ligands with cyclopentadienyl or cyclooctatetraenyl ligands in the coordination sphere of lanthanide ions. The first lanthanide complexes containing both benzamidinate and pentamethylcyclopentadienyl bonded to yttrium was reported by Teuben et al. Yttrium aryloxides as well as anhydrous yttrium trichloride can be used as starting materials in these preparations (Eq. 19, Scheme 5) [27] ... 

More recently this chemistry has been successfully extended to disubstituted yttrium derivatives [27]. The THF adduct of yttrium trichloride reacts with two equivalents of Li[Me2Si(OfBuXNtBu)] (11) to afford the ate-complex 67b, which can be transformed into the THF solvate 68b by treatment with pentane under reflux conditions (Scheme 7). 

The synthesis of the corresponding organolanthanide chlorides was performed by transmetallation of the dilithium salt with anhydrous lutetium or yttrium trichloride. Metallocene dichloro complexes [(/ ,Y)-Me2Si(C5H3But)((+)- -Men-Cp)]Ln(/r-Cl2)Li(OEt2)2 (Ln = Y, Lu) were synthesized by treatment of the corresponding lanthanide trichlorides with the dilithium salt of the ligand and isolated isomerically pure by crystallization from diethyl ether (Scheme 162).650... 

YCI3 YTTRIUM TRICHLORIDE 1818 ZnTe ZINC TELLURIDE 1849... 

Finally, in this section on alcohols, we should mention investigations in which the trichloride/alcohol systems are acknowledged to be not anhydrous. Solubilities of yttrium trichloride and of most of the lanthanide trichlorides have been determined in 96.8% ethanol over the temperature range 20-60°C (289), while the solubilities of the hydrates LaCl3-7H20 and CeCls-BHjO have been determined in an extensive range of alcohols at 25°C, with a few data at 35° and at 45°C (290). 

Scandium trichloride and yttrium trichloride react with methyl lithium as well as with phenyl lithium yielding air-sensitive products. But only the phenyl derivatives could be isolated and definitely characterized (Hart and Saran, 1968 Hart et al., 1970) ... 

Interesting partial substitntion reactions between yttrium trichloride and sodinm tert-butoxide in different (1 2 and 1 3) molar ratios have been reported (Eqs 2.45 and 2.46)... 

In order to produce Y203-stabilized zirconia with homogeneous distribution, sol-gel processes or coprecipitation have been adopted, based on the hydrolysis of stoichiometric mixtures of zirconyl chloride and yttrium trichloride (see, e.g.. Carter et al, 2009). The hydroxides formed are subsequently subjected to aceo-tropic distillation, drying, calcining between 850 and 950 °C, wet milling, and spray-drying. 

The local structure of a molten lanthanide trichloride was studied for the first time by Maroni et al. (1974) who investigated the LaCl3-KCl binary mixture. The conclusion of the existence of at least one highly symmetrical associated species in this melt based on the analysis of Raman spectra was soon substantiated in the case of yttrium trichloride (Papatheodorou, 1977). In the latter work, the high-symmetry structural unit was identified as the octahedral hexachloride (YCle) . Next, a comparison of the Raman spectra of liquid and solid yttrium trichloride samples led the authors to conclude that lattice-type vibrations occurred in melts. 

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